If there are default groups that largely meet your needs and you only want to make a few changes, you can do so easily. However, be sure to follow these steps, otherwise the group will be overwritten during the next update and your changes will be lost.
Procedure in the FM Portal
Path to the starting point: Control Panel - Portal Options - Rights Management - Groups and Rights
Find the permission group you want to customize and open it.
Change the code of the permission group. Make sure it is different from the codes of all other permission groups.
Uncheck the Automatic Group box.
Click Save in the toolbar.
Now you can customize the permission group as you wish. The next time the FM Portal is updated, the automatic group on which you based your customizations will be created as a new permission group. Your permission group will remain exactly as you set it.
See here for the configuration options available in the calculation group: 📄 Einstellungsmöglichkeiten von Rechtegruppen IC1063