Basic permissions are included in Starter and Plus plans. It will let you select between two permission groups, Owner access and Staff access.
Basic permissions grants you the ability to edit the name and exact permissions for the permission group not labeled "Owner Access". However, you are unable to create new permission groups. Therefore, the page has a lock icon next to it in the menu.
When you click on Permission Groups, you will see the page below.
The Owner Access group is not editable, however you can edit the Staff Access permission group.
Advanced permissions are included in Platinum and Enterprise plans. Advanced permissions gives you the ability to create more than two permission groups and manage those permission groups at a very granular level.
To add permission groups, just click on +New Permission Group.
Name your permission group, select the access they will be provided for each category, and save once done.
You can always delete the permission group/s you have created by clicking on the x button next to it.