docs: update progress indicator usage tab

src/pages/components/progress-indicator/usage.mdx

@@ -10,16 +10,19 @@ import A11yStatus from 'components/A11yStatus';
 
 <PageDescription>
 
-A progress indicator is a visual representation of a user's progress through a
-set of steps, guiding toward the completion of a specified process.
+A progress indicator guides users through any linear, multistep task by showing
+the user their completed, current, and future steps.
 
 </PageDescription>
 
 <AnchorLinks>
 
 <AnchorLink>Live demo</AnchorLink>
 <AnchorLink>Overview</AnchorLink>
-<AnchorLink>Best practices</AnchorLink>
+<AnchorLink>Formatting</AnchorLink>
+<AnchorLink>Content</AnchorLink>
+<AnchorLink>Behaviors</AnchorLink>
+<AnchorLink>Related</AnchorLink>
 <AnchorLink>Feedback</AnchorLink>
 
 </AnchorLinks>
@@ -45,41 +48,220 @@ set of steps, guiding toward the completion of a specified process.
 
 ## Overview
 
-Use progress indicators to keep the user on track when completing a specific
-task. By dividing the end goal into smaller, sub-tasks, it increases the
-percentage of completeness as each task is completed.
+Progress indicators help manage a user's expectations when completing a
+multistep process. They show which step the user is currently on, the total
+number of steps, and overall progress in completing a task.
 
-## Best practices
+<Row>
+<Column colLg={8}>
+
+![Example of a progress indicator used in a payment UI](images/progress-indicator-usage-1.png)
+
+<Caption>
+  Example of a progress indicator used in a payment UI.
+</Caption>
+</Column>
+</Row>
+
+### When to use
+
+- When the user is working through a linear process that can be organized into
+  three or more steps.
+- When the user could benefit from understanding their progress on long forms
+  such as eCommerce checkouts, onboarding, or visa applications.
+- When user inputs should be validated before progressing to the next step.
+- To complement standard back/next navigation in a linear sequence.
+
+### When not to use
+
+- When a process or form has fewer than three steps.
+- When the process may be completed in any order.
+- When the number of steps may change based on conditional logic.
+
+## Formatting
+
+### Anatomy
+
+<Row>
+<Column colLg={12}>
+
+![Progress indicator anatomy](images/progress-indicator-usage-2.png)
+
+</Column>
+</Row>
 
-#### Logical progression
+1. **Status indicator:** Communicates if a step is completed, incomplete, not
+   started, or has an error. See the
+   [status indicator pattern](/patterns/status-indicator-pattern/) for guidance.
+2. **Active step line:** Indicates completed steps and the step the user is
+   currently on.
+3. **Label:** Communicates what the user will accomplish in each step. Numbering
+   each step also makes the progression more obvious.
+4. **Inactive step line:** Indicates incomplete steps as well as steps that are
+   in an error, disabled, or skeleton state.
+5. **Helper text:** Labels a step as optional or in an error state.
 
-Display the steps in order from left to right. Indicate to the user that they
-are performing a multistep process, and show the direction of movement. Allow
-the user to return to a previous step to review their data submission.
+### Alignment
 
-#### Indicate the current step
+Progress indicators can be in vertical or horizontal positions depending on the
+use case and the structure of the UI. When possible, arrange the progress
+indicator vertically for easier reading.
 
-Keeping the user informed of where they currently are within the process or task
-at hand will give them a sense of control. This helps the user to know where
-they are in relation to where they have been, and what sections are to follow.
-Clear labels should accompany the progress indicator to indicate what the user
-will accomplish within each step. Keep labels between one to two words.
+<Row>
+<Column colLg={12}>
+
+![Example of a progress indicator used with vertical alignment](images/progress-indicator-usage-3.png)
+
+<Caption>Example of a progress indicator using vertical alignment.</Caption>
 
-#### Validation
+</Column>
+</Row>
 
-Use validation to confirm that a previous step has been completed. If the user
-cannot proceed onto another step without first completing a task, use an
-[Inline Notification](/components/notification/code#inline-notification) to
-inform them.
+### Placement
+
+The progress indicator component can be placed on a full page, in a modal, or in
+a side panel. It is also common to use the progress indicator in a
+[tearsheet](https://pages.github.ibm.com/cdai-design/pal/components/tearsheet/usage/),
+a component provided by Carbon for IBM Products.
 
 <Row>
 <Column colLg={8}>
 
-![Example of the progress indicator in a payment UI](images/progress-indicator-usage-1.png)
+![Examples of progress indicators on a full page, tearsheet, and side panel](images/progress-indicator-usage-4.png)
+
+<Caption>
+  Examples of progress indicators on a full page, tearsheet, and side panel.
+</Caption>
 
 </Column>
 </Row>
 
+## Content
+
+### Main elements
+
+#### Label
+
+The label should communicate what the user will accomplish in each step in one
+or two words. One option is to clearly indicate the action of the step by using
+the {verb} + {noun} content formula. For example, "Configure IdP" or "Define
+endpoints." A label may use one word if it is universally understood, such as
+"Cart," "Shipping," or "Payment." Avoid vague terms like "Processing." You may
+also number each step to make the progression more obvious.
+
+#### Helper text
+
+Use the helper text to indicate that a step is optional or that a step is in an
+error state.
+
+### Overflow content
+
+#### Label
+
+When there is not enough space, consider rewording the label or truncate the
+label text with an ellipsis and provide a tooltip to convey additional
+information.
+
+#### Helper text
+
+Long helper text may wrap to a second line, and this is preferable to
+truncation. Wrap the helper text beneath the label so that both maintain left
+alignment.
+
+<Row>
+<Column colLg={12}>
+
+![Example of progress indicator with overflow content](images/progress-indicator-usage-5.png)
+
+<Caption>
+  Example of a helper text that wraps to the second line and maintains left alignment with the label.
+</Caption>
+</Column>
+</Row>
+
+### Further guidance
+
+For further content guidance, see Carbon's
+[content guidelines](/guidelines/content/overview/).
+
+## Behaviors
+
+### States
+
+The progress indicator has seven states: **completed**, **current**, **not
+started**, **error**, **disabled**, **hover**, and **focus**. View the
+[Style](/components/progress-indicator/style/) tab for visual specs of each
+state and see the
+[status indicator pattern](/patterns/status-indicator-pattern/) for additional
+guidance.
+
+| State       | Description                                                                                                                                                                                                                                                                                                                                   |
+| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| Completed   | A step is complete when a user has filled out the required information within a step and progressed to the following step. When possible, use validation to confirm that a step has been completed before the user continues. All steps that have been completed are indicated by an outlined circle with a checkmark and a blue active line. |
+| Current     | A step is current when a user is interacting with the information within that step. The current step the user is on is indicated by a half-filled circle and a blue active line.                                                                                                                                                              |
+| Not started | A step is not started when a user has not yet interacted with that step. Steps the user has not encountered yet, or future steps, are indicated by an outlined circle and a gray active line.                                                                                                                                                 |
+| Error       | A step may be in error when a user has entered invalid or incomplete information. There could also be a server-side error. Provide clear information about the error and guidance on how to resolve the issue.                                                                                                                                |
+| Disabled    | A step is disabled when all interactive functions have been removed. Unlike read-only states, disabled states are not focusable, are not read by screen readers, and do not need to pass visual contrast, making them inaccessible if they need to be interpreted.                                                                            |
+| Hover       | Use the hover state when a user's mouse cursor is hovering over the progress indicator's step.                                                                                                                                                                                                                                                |
+| Focus       | When a user tabs to or clicks on the progress indicator's step, the step becomes focused, indicating the user has successfully navigated to the component.                                                                                                                                                                                    |
+
+### Interactions
+
+By default, the progress indicator is not interactive, providing only a visual
+update of the users' progress. There is also an option for an interactive
+progress indicator, which allows users to navigate to each step.
+
+#### Mouse
+
+If the progress indicator is interactive, users can navigate to a step by
+clicking anywhere within the step label container.
+
+<Row>
+<Column colLg={12}>
+
+![Example of an interactive progress indicator](images/progress-indicator-usage-6.png)
+
+</Column>
+</Row>
+
+#### Keyboard
+
+The first step should be selected by default. Users can navigate between steps
+by pressing `Right` or `Left` arrow keys. For additional keyboard interactions,
+see the [Accessibility](/components/progress-indicator/accessibility/) tab.
+
+### Validation
+
+When possible, use validation to confirm that a step has been completed before
+the user continues. If any entry is invalid, the progress indicator should show
+an error state. Additionally, the invalid entry should be marked with an error
+state and include an inline error message that helps the user understand the
+problem and how to fix it. This kind of inline validation (or client-side
+validation) should happen as soon as the field loses focus.
+
+If the user cannot proceed due to a server-side issue, then an
+[inline notification](/components/notification/code#inline-notification) should
+appear.
+
+<Row>
+<Column colLg={12}>
+
+![Example of a progress indicator using validation](images/progress-indicator-usage-7.png)
+
+<Caption>
+  Example of a progress indicator using validation.
+</Caption>
+</Column>
+</Row>
+
+## Related
+
+- The progress indicator component is commonly used in
+  [dialogs](/patterns/dialog-pattern/) or [forms](/patterns/forms-pattern/).
+- It is also common to use the progress indicator in a
+  [tearsheet](https://pages.github.ibm.com/cdai-design/pal/components/tearsheet/usage/),
+  a component provided by Carbon for IBM Products.
+
 ## Feedback
 
 Help us improve this component by providing feedback, asking questions, and