Problem: How to "assign" uploaded content to site users so that only they can view it.
Solution: The most straightforward assignment is by making the users the post authors of the content.
Then create a View to display posts of the currently logged in user, which means that other users will not see the content.
Relevant Documentation: https://toolset.com/documentation/user-guides/filtering-views-query-by-author/
This is the technical support forum for Toolset - a suite of plugins for developing WordPress sites without writing PHP.
Everyone can read this forum, but only Toolset clients can post in it. Toolset support works 6 days per week, 19 hours per day.