Installing an App on Android is easy.

Before you can install your app you need to:

1. Generate the app.
(How do I generate an app?)

2. Install your App
In Develop,  Use the App Menu then select Show Builds


To install Android Test Apps you will need to enable installing apps from outside of the Play Store:
Check the Unknown Sources option in your device's Settings.

Depending on what version of Android your device is running, the Unknown Sources setting will either be under Security (on newer devices) or Applications (on older devices).

Then select the Build you want to install.

To install the app you can use a QR code Reader app or enter the short URL then the code

More on Installing an App on your device