Automatically grant in-game admin rights
Step 1: Access the game server
Go to the game server overview page, and click the name of the game server.
Step 2: Add steam ID to Admin ID list
Add the Steam ID to the bottom of the Admin ID list, to automatically grand this user admin rights on login.
Please do note that you are required to restart the game server for these changes to take effect.
Make sure to save the changes when you are done.