Unfortunately my tutorials are mostly for the company where I work, or on very advanced topics (Co-Location, Room Reconstruction). Here are the Oculus Unity samples: https://github.com/oculus-samples. I recommend starting with https://github.com/oculus-samples/Unity-StarterSamples. I'm a Unity dev primarily, so I don't have much advice on the Unreal side.
My best advice is to find some mechanics in other games that you like. Here is the list of ones I recommend for the cozy-dark feel.
a fisherman's tale (short)
Moss (medium)
the last clockwinder (short)
Budget Cuts (medium)
Walkabout Mini-Golf (party)
Demeo (surprisingly long, you can only save between levels)
Virtual Virtual Reality (medium)
The things that will drive the VR design are locomotion. I was thinking of building the boids app in VR with the hands being fish like the planes in Xortex from The Lab.