The hand tracking test will be available to you once you've updated the Quest to v12.

Third-party apps with hand tracking won't come until 2020. However, Oculus will offer a development kit next week that will make hands-only control available. The technology won't necessarily make sense in every app. We can imagine it being a particular problem in games where your hands might be out of view of the headset's cameras. It's a start, though, and there may come a time when you only pick up the controllers when you absolutely need them.