Thank you very much - I was a little bit confused with using a German version.....

Activate Developer Mode:

• Go to the Settings module.
• Scroll to the bottom and click "Activate the Developer Mode" (found in the Debug section).

Enable Multicompany Feature:

• Still, in the Settings module, search for "Companies."
• In the search results, you should see an option to enable "Multi-Company." Toggle this option on.

Create Additional Companies:

• Once the multi-company feature is enabled, go to Settings > Companies (or use the search bar to find it).
• You can add new companies by clicking "Create" and filling in the necessary details here.

Assign Users to Companies:

• Go to Settings > Users & Companies > Users.
• Open a user’s profile and scroll to the Access Rights section, where you can assign the user to one or more companies.