From the very basic google search I've just done, it seems like the game isn't supporting native VR. (Talking about Outlast 2, but I guess if the second game doesn't the first one wont either)
Now, even if native support isn't a thing in this game, you can try playing around with VorpX. Wont be as good, but it'll do the trick.
https://www.youtube.com/watch?v=IX-WZ5VheiA
Grrr... Thought it was native support
How painful is it to setup/use VorpX? - Never even heard of it
EDIT: Spotted this somewhere else too as regards using it VorpX - "Outlast has to be started in 32bit mode. Either by starting the 32bit executable directly or with the parameter -32 in Steams launch options for the program." - Sigh!