Open horizon.mywallst.com in Safari on your iOS mobile device
Log in (if required) and navigate to the Home tab
Tap the Share option for Safari

Scroll down the list of options, then tap Add to Home Screen.
After tapping Add to Home Screen you will then see a preview of the app icon and the app name and you can then tap Add
Once added you may need to login again on the app you have now set up
Open horizon.mywallst.com in Google Chrome on your Android mobile device
Log in (if required) and navigate to the Home tab
Tap the Chrome Menu icon (3 dots in the upper right-hand corner)
Scroll down the list of options, then tap Add to Home Screen.
After tapping Add to Home Screen you will then see a preview of the app icon and the app name and you can then tap Add
Once added you may need to login again on the app you have now set up