If you are a server Administrator, you can add other users to "Administrator" role. Go to Administration (link at the top right of any web page on the server), then "Permissions". There you can add more users to Administrator role.
If you don't see Administration, Permissions section, it means that you are not the administrator on the server.
By default, the administrator on the server is:
If for some reason you can't figure out who Administrator is, you can still add one from command line after the server is installed.
You can add administrators from command line.
Before you can add administrators, you need to stop Starship Server:
On Windows
Open command prompt where StarshipServer.exe is (usually in "Program files x86/Starship Server") and type:
Starship Server stop
On Linux
Stop Starship Server process
Windows authentication
In Windows authentication you only add username, for example
StarshipServer addadmin -u domain\\username