As Gutenberg is in development the only way you can try it is to install it as a plugin.
Note: Do Not Use Gutenberg On A Live (Production) Site. You May Get Unintended And Irreversible Results. Try Gutenberg Only On A Test Site Or A Clone Of Your Live Site
There. I told you. Fair warning.
Once you install the Gutenberg plugin, you’ll see there is a demo page to help you poke around to get familiar with it’s features.
And that is exactly what I do in my video.