Follow the instructions at the link to sign up for the Beta program:
Nova Launcher Beta
This will allow you to install the beta version directly from Google Play instead of having to side-load it.
I refuse to use any launcher without gestures. It doubles the functionality of icons.
BTW, can anyone explain the difference between swiping to the Google Now screen on the GN Launcher and long pressing the home key for Google Now? If you don't want to wait the half second for it to activate, you could also set up a gesture in Nova to launch it. Personally, the fact that I can long press home for GN from any screen makes it automatically a better option. I am baffled people are installing GNL for the GN screen. To be honest, GNL is even less customizable than TW Launcher and would be dead last on my list of options.