Update README.md with installation instructions and usage examples for perisso

Author: runxel

README.md

@@ -7,12 +7,33 @@
 _Tapir_ provides a collection of tooling to assist the usage of the JSON API of Archicad.  
 _Perisso_ is a Python package based on this fantastic work and aims to make it even easier to interact with and manipulate digital architectural model elements, by employing a fluent interface. This includes offering an efficient way to filter elements based on various criteria.
 
+
+## Installation
+
+1. Make sure you have the Tapir plugin for Archicad installed.
+2. Install `perisso`.  
+My recommendation: Always use [uv](https://docs.astral.sh/uv/). Use it for everything.
+
+```bash
+uv venv
+uv pip install perisso
+```
+
+Alternatively, you just download the source files. Oldschool.
+
+
 > [!WARNING]  
 > Perisso is under development. Please expect breaking changes between versions.
 
+
 ## Usage
 
-Here is a basic example of how to use the `perisso` package:
+The simplest way is to just call `perisso()`. This will select all elements by default. To limit the elements to the current selection in Archicad use the `selection` parameter:
+```python
+sel_elem = perisso(selection=True)
+```
+
+Here is a basic example of how to use `perisso`:
 
 ```python
 from perisso import perisso, Filter, ElType
@@ -22,8 +43,23 @@ filtered_elements = elements.filterBy(Filter.ELEMENT_TYPE).equals(ElType.COLUMN)
 print(filtered_elements)
 ```
 
+> [!CAUTION]
+> The resulting element list is compatible with Tapir, but _not_ with the native [Archicad-Python connection](https://pypi.org/project/archicad/).  
+For that you need to call the `toNative()` function on the perisso collection. The result uses the classes of the AC-Py connection and can then be fed into it.
+
+
+See the [examples](https://github.com/runxel/perisso/tree/main/examples) for more.
+
+
+> [!NOTE]  
+> If a filter does _not_ apply the element concerned is silently removed (not _included_ in the result, that is). Example: A Property is not used on it.
+
+
+## Contributing
+
+Please open an issue or submit a pull request for any enhancements or bug fixes. Contributions are welcome, but might not be accepted until `perisso` reached a somewhat stable state.
+
+
 ## License
 
 Perisso is licensed under the MIT License.
-```
-