I found out how to do this through trial and error, but if you played the iOS or android version of Exedra, then you'll probably want to move your account to the steam release as opposed to starting over. The game can be finicky- it won't let you do this unless the action is performed a certain way, as detailed in this short guide.

Make sure you have data transfer set up first

If you delete your account without doing this, then it'll be permanently lost. In the menu settings, choose data transfer, transfer ID, and create a password. Write both down/screenshot them afterwards. You can also link social media if need be.

Instructions

1. Choose return to title. For some reason, you have to be on the title screen for this method to work properly. When I tried it on the main hub, my game signed in but I was still stuck on the new account created after going through the tutorial a second time. My goal here was to switch to my old account.
   
2. Click support to open a smaller settings menu.
   
3. In data transfer, enter your ID and password. If that doesn't work, then signing in with google, twitter, or facebook is a second option.
   
4. Click ok. The game should restart.