In your browser on your iOS device, tap share at the bottom of the screen, and then select "Add to Home Screen". Personal Ground Control (PGC) will start installing itself as an app on your iOS device.
In your browser on your Android phone, open the menu, usually the "⋮" symbol in the top right. Scroll down and select "Add to Home screen", and then select install. Personal Ground Control (PGC) will start installing itself as an app on your phone.