Please note: all credit goes to RueShejn!
This will show you how to convert your steam guest account into a registered account.
Guide to Convert Guest Account to Registered Account
- Login to the game and select your character.
- Open the ESC menu and click settings.
- Click Privacy then “Account Linking”.
- Choose an account to link and follow the steps there.
- If it all worked out you should be able to log out and then click the guest account button on the bottom left and then choose “existing account” and choose the account you linked in step 4.
You should now be done.
Make sure your on the same game server you have your character in and it should be there.
Linking your account is needed if you want to play on mobile.