Google makes it easier to try out the Android Q update for those with Pixel devices, including the original Pixel, Pixel 2, and Pixel 3 generations. Otherwise, you could run an Android emulator if you don't have a Pixel phone.
Either way, it's probably not worth upgrading to the beta version of Android Q right this second, as updates and features won't be fully fleshed out yet, and you'll likely face bugs that will affect how you use your phone on a day-to-day basis.