There are three default role levels in Media Pocket admins, defaults, and guests.
Admins: "Super-users" that can see, edit and delete all the assets uploaded to the environment. Admins control the trash bin, have the right to edit users, manage billing information, create custom fields, create publishing channels and see statistics.
Defaults: "Basic members" that can see all the assets in the projects they belong to. Defaults can upload and manage assets, delete their own assets, create and manage projects, delete their own projects and invite guests. See how to invite guests.
Guest: "Visitor" that can belong to only one project, collection or drop at a time. Guests can only add and edit their own assets and upload material to placeholders, but they cannot remove anything nor invite more guests. Guests are not allowed to share assets via link or publishing channels. See how to invite guests.
User Roles -tool
On the users -page, admins are able to create custom user roles by clicking the create -button, and edit/delete created roles (not system default).
On the details -page you are able to add a name + description to role, on the permissions -page you can choose the permissions you can choose the permissions you want to add for the role, and on the users -page you'll see the users that have the role.
You can assign users to role by editing existing user, or choosing the new role when you are adding a new user.