When you open the app, you'll see a portal you can step through. Once you do, you can explore a cave in which you can find glyphs to interact with (while still being able to look at the real world). Track down all of them and the app will let you explore "more worlds throughout Childish Gambino's universe."

You can check out Pharos AR on Android now and it'll arrive on iOS soon. You'll be able to experience it with your friends regardless of which phone each of you have, because the app uses ARCore's Cloud Anchors API.