Unturned: How do I register an admin on my server?
Adding admins in the web interface
Step 2: Enter your SteamID64 under the Owner field or the Admins field and click on Save.
How do I find my SteamID64?
Here we will briefly show you how to find your SteamID64, which you will need to make yourself admin. Go to steamid.co and enter your Steam display name there.
In this case the SteamID64 would be 76561197994023767.