website builder with C5
1. Allow users' registration
2. Add a sub page like domain.com/user/
3. Give the user full access to his/her created page.
4. Allow him/her the proper use of File Manager files
This could be a fairly significant sized customization, there are a number of moving parts, and a number of options for automation that you may have preferences for. Those should be identified ahead of time for a successful outcome.