Simple guide on how to get online co-op!
How to Start Remote Play
For playing with a friend you need the friends list open on Steam.
If you have the game open you can now see a Blue Button, next to text saying “Invite Anyone To Play” that button is used to open the “Remote Play Menu” wich is needed.
Add a Friend
You have a copple of Options on how to invite the person!
(You do not need to be the friend of the person you are trying to play with)
Copy link as showed in picture below and send to Friend.
Right click a friend in your friend list and click invite to play.
Now In Game
Once in with both players select a Save or start a new one.
Select Local co-op.
Both players can now Press X/A to enable choose their character.