Upload documents to agenda; request documents to participants
You can upload a document to the whole meeting by clicking on "Documents" in the top-right corner in the meeting edit mode. The number next to "Documents" indicates the number of files currently attached:

You may drag and drop a file or add a link to a website or internal resource:

If you scroll to the bottom, you have the option to attach a document or add a link to an individual agenda item, rather than to the whole meeting:


Another option is to open the specific agenda item from the agenda view and to add documents there:


You can now decide to add a document or link for the specific agenda item yourself:

Alternatively, you can request a user to add the necessary documents instead. Select the desired user, then add a due date & time and a message if needed:
