The most popular VR headset of 2019/2020 was the Oculus Quest and Quest 2. These are low-cost, walk-around headsets that provide a great introduction to VR for many people. It can be a bit fiddly to set up a Quest for Unity project development, so we'll go through the steps required in this short recipe. Between this and the next recipe, you'll have the satisfaction of creating VR projects and loading them onto your headset.
These steps were performed at the time the book was being written. But things change fast, and it may be that not all the steps/screenshots are the same when you attempt this developer mode setup. However, we have included this recipe since we believe it will still be helpful to those beginning development for the Quest/2 to see the kinds of actions they'll need to take.