How to start a co-op/multiplayer game?

[riri]

So my partner and I have bought a few multiplayer/co-op VR escape room/puzzle type games from steam. Our plan was one of us was going to play using the HTC vive cosmos and the other was going to play with the computer it's connected up too. But we have tried tales of escape, escape first, eye in the sky and the experiment escape room and have had absolutely no luck, the VR player gets to the host room or whatever it is but we don't really know what we're supposed to do from there, so we tried creating a game but can't seem to join up from the computer. What are we supposed to do to be able to play co-op/multiplayer together? They're co-op/multiplayer games so that's not the issue and we've managed to play black hat cooperative together from the VR and computer with no problems so that's not the issue either. Anything would help we have no idea what to do! Surely it shouldn't be that hard to start a co-op game..