Hello. To install iCoup as PWA on your device read and follow this instruction.

Process of installation is slightly different for iOS (iPhone) and Android devices.

iCoup as PWA can only be installed on iOS using the Safari web browser so as a first step you have to open this page in Safari. Then tap the "Share" button and select "Add to Home Screen" from the popup. Lastly, tap "Add" in the top right corner to finish installing the PWA. It will now be on your home screen. See screenshots below.

If you are using Android then you may use the browser of your choice. Instruction below shows example for Chrome browser, but I was also able to do the same for Brave browser. Open Chrome browser, then tap "Three dots" button in the top right area of application, and select "Add to Home Screen" from the popup. Then tap "Install" button that will slide from the bottom part of the screen. And lastly tap "Install". See screenshots below.