You're not really supposed to need one in UE4 if you use a Rift. You just need to create a VR project and it should work for a basic level.
For a Quest, it's a bit more complicated. And I only know of one video on YouTube. https://www.youtube.com/watch?v=jlcj4HB9LX8 I haven't tried it. I've decided to focus on Unity development.
Yes I am talking Quest, and I did get as far as getting the template VR project running, until latest firmware update broke ADB on my windows 7. But I was talking more of a do's and dont's/tips, etc.