You only need to do this once, the first time.
Click the
Publish tab, and then click
BloomPUB.
Below Help, click
Get Bloom Reader App.
Alternatively, go to https://play.google.com/store/apps, and then search for SIL Bloom Reader.
You need to have a Google account.
Download and install the app on your Android device.
Detailed steps are beyond the scope of these Bloom Helps. Various Internet sites give instructions. Here is one:
https://www.androidcentral.com/android-apps-install.