Add docs for "Play Request" feature in Software Catalog

content/en/internal_developer_portal/software_catalog/entity_model/entity_types.md

@@ -187,7 +187,6 @@
 {{< /code-block >}}
 
 **File reference:** 
-
 Point to an OpenAPI file stored in GitHub using the `fileref` field.
 
 {{< code-block lang="yaml" filename="entity.datadog.yaml" collapsible="true" >}}
@@ -219,9 +218,29 @@
 
 This page holds relationship data of how the API interacts with dependencies, the API components, an OpenAPI preview, and logs and events aggregated across all endpoints. 
 
+**Test API Endpoints** 
+
+You can use the **Play Request** feature in Software Catalog to send test HTTP requests to your endpoints and inspect the responses. 
+
+To send a test request: 
+
+1. Navigate to an endpoint in Software Catalog.
+2. Click an endpoint to open its details in the side panel.
+3. Click **Play Request** to configure and send the request.
+
+{{< img src="/tracing/software_catalog/play-request.png" alt="Play Request modal to test API requests in Software Catalog" style="width:90%;" >}}
+
+Before sending the request, you can configure the following: 
+- **Inputs**: Provide values for any required query parameters, path variables, or request body fields.
+- **Authentication**: Select an authentication method if required by the endpoint.
+- **Location**: Choose where the request should be sent from:
+    - Public Location (default)
+    - Private Location, for APIs accessible only within your private network. These must be configured using [Synthetics Private Locations][2]. Any Private Locations you've already set up appear automatically in the dropdown.
+
 **Note**: Software Catalog contains HTTP endpoints that are automatically discovered by APM. The concept of endpoints correspond to [APM resources][1] for an APM web service.
 
 [1]: /tracing/glossary/#resources
+[2]: /synthetics/platform/private_locations
 
 {{% /tab %}}