While you can download the APKs here directly, you should preferably use an F-Droid client so the app stays up-to-date on your device. Some clients have this repo enabled by default, e.g. Neo Store, Droid-ify, or, of course, the IzzyOnDroid client by Sunil. With others (like the official client) you'll have to add this repo manually (see the hint on top of the package list for how to do that).