Create nested Learning Module / Folder content structure in a Blackboard Learn Ultra course via the REST Content API

Steps

1. List root-level content with GET /learn/api/public/v1/courses/:courseId/contents, then POST to the same endpoint with a contentHandler for a Folder or Learning Module type to create a top-level container.
2. Create child content by POSTing to /learn/api/public/v1/courses/:courseId/contents/:contentId/children, nesting Documents, Files, or other items inside the container you just created.
3. Keep in mind that Ultra course content only supports two levels of nesting: a Learning Module can contain Folders, but a Folder cannot contain another Learning Module or Folder beneath it.
4. If students should move sequentially through a module's items without returning to the course content list, configure the Learning Module's forced-sequence behavior rather than trying to replicate it with a Folder.
5. Retrieve or update a specific content item with GET/PATCH /learn/api/public/v1/courses/:courseId/contents/:contentId once created, to adjust availability, position, or metadata.