Adding yourself as an Admin
To add yourself as an admin, you will first need to find your SteamID64
The easiest way to do this is by using the following website http://steamid.io/
You can either enter your CustomURL or login through steam to find your SteamID64.
From here, you will want to open your servers Game Panel and go to Configuration Files.
Here you want to edit the SpaceEngineers-Dedicated.cfg in the text editor.
Scroll to the bottom of the configuration file and you will see the following lines.
<Administrators>
<unsignedLong>76561198037107686</unsignedLong>
</Administrators>
Here you simply want to replace the current SteamID64 (This is just a placeholder) with your own.
eg.
<Administrators>
<unsignedLong>76561197985795975</unsignedLong>
</Administrators>
Too add multiple admins, simply add more SteamID64s under new unsignedLong headers
eg.
<Administrators>
<unsignedLong>76561197985795975</unsignedLong>
<unsignedLong>76561198037107686</unsignedLong>
</Administrators>
After saving this config and restarting your service you should now be admin!
Important: If after restarting your server you notice the changes have not been applied, you can try and delete the LastSession.sbl file in the Saves (Inside Settings) folder to make sure everything is applied properly.
Admin Commands
Admin Commands only work on the development branch of this game, however there is an in game admin menu.
To open this menu, join your server and press ALT + F10 in game.