Don't use manager for that. As you can imagine manager has all permissions on the site.
Please check in the official documentation for other alternatives. in short:
- Site Consumer - can read content
- Site Contributor - can create and upload content
- Site Collaborator - can do everything except moving and deleting other users content
- Site Manager - full access
If none of them are useful for you, you can create a custom permission (check the official documentation, the part that start with "Now, sometimes these roles are not enough to set up the permissions we need").
I hope this info helps you!
Cheers.
