Update coreTypes.md

Author: tylercleveland2

graph/articles/coreTypes.md

@@ -19,8 +19,8 @@ The following types are identified as core types, and will require strong justif
 Instead of adding a structural property to the existing type (`user`, `group` or `device`), create a new type that models the information captured in the proposed structural property(s).
 Then, do one of the following:
 - Add a navigation property on the existing type to the new type, containing the new type.
-- Contain the new type in an entity set elsewhere, and add a navigation property to the existing type on the new type.
 - Contain the new type in an entity set elsewhere, and add a navigation property to the new type on the existing type.
+- Contain the new type in an entity set elsewhere, and add a navigation property to the existing type on the new type.
 
 ## Example:
 
@@ -39,19 +39,59 @@ Don't add new properties to core types such as `user`.
 
 ### Do:
 
-First, create a new type that models the information captured in the desired structural property(s).
+Do one of the following:
 
+#### Add a navigation property on the existing type to the new type, containing the new type.
+
+Define the new entity type:
 ```xml
 <EntityType name="bankAccountInformation">
     <Property Name="accountNumber" Type="Edm.string"/>
     <Property Name="routingNumber" Type="Edm.string"/>
 </EntityType>
 ```
 
-Then, for example, add a navigation property on the existing type, containing the new type:
-
+Add a contained navigation from user to the new entity type:
 ```xml
 <EntityType name="user">
     <NavigationProperty Name="bankAccountInformation" Type="bankAccountInformation" ContainsTarget="true"/>
 </EntityType>
 ```
+
+#### Contain the new type in an entity set elsewhere, and add a navigation property to the new type on the existing type.
+
+Define the new entity type:
+```xml
+<EntityType name="bankAccountInformation">
+    <Property Name="accountNumber" Type="Edm.string"/>
+    <Property Name="routingNumber" Type="Edm.string"/>
+</EntityType>
+```
+
+Contain the new entity type in an entity set or singleton:
+```xml
+<EntitySet Name="bankAccountInformations" EntityType="bankAccountInformation">
+```
+
+Add a navigation from user to the new type:
+```xml
+<EntityType name="user">
+    <NavigationProperty Name="bankAccountInformation" Type="bankAccountInformation" />
+</EntityType>
+```
+
+#### Contain the new type in an entity set elsewhere, and add a navigation property to the existing type on the new type.
+
+Define the new entity type, with a navigation to the user:
+```xml
+<EntityType name="bankAccountInformation">
+    <Property Name="accountNumber" Type="Edm.string"/>
+    <Property Name="routingNumber" Type="Edm.string"/>
+    <NavigationProperty Name="user" Type="microsoft.graph.user" />
+</EntityType>
+```
+
+Contain the new entity type in an entity set or singleton:
+```xml
+<EntitySet Name="bankAccountInformations" EntityType="bankAccountInformation">
+```