Follow the below steps to install the Android app APK we have shared with you for testing.
Download the APK we have shared with you on the connected device (Desktop/Mobile).
Open your Android device's file explorer app.
Locate your APK file in your file explorer app and select it.
The APK installer menu will appear—tap Install.
There are two ways to install the app from an unknown source:
Navigate to Settings. > Apps.
Tap the Menu icon (upper-right).
Click Special access.
Click Install unknown apps.
Select the unknown app, then tap the Allow from this source switch to turn on or off.
Click the Downloaded file
A pop-up will appear and tap the Settings bar
Install apps from external sources will appear, then Switch on/off the Allow app status.
Tap Install and the updated app will open.
5. Allow time for the app to install.
6. Tap Done or Open once the installation is complete.
Note: If you have a test app installed already on the mobile, uninstall it and follow the above steps.