1. In the Admin tab, click on "Users" sub tab.
2. Find the user and click on "Set Roles" on the right. All users should have Basic Read Access by default.
3. In the "+ Add Role" drop-down, select a new role. You can add multiple roles. Or, click on "x Remove" on the right to delete an existing role.
4. Click "Save" at the bottom of the form. You now should see the role updated in the list.