The instructions message to add the App to the home screen of an iPhone, can be edited in text lines 1 and 2.
You can also change the color off the text, background, borders, and even customize the pop-up window to display it in the center of the screen, overlay it in black, display the short name of the app and icon, etc.
Clicking the "Next" button will display the Facebook PWA pop-up settings screen.
Here you will also find the url link to access the PWA, along with the QR code to be able to download the PWA.
On the other hand, if you have added a custom domain for the PWA, it will also be displayed here.
And finally, if you click on the "Click here to add custom CSS" button, a new browser window will open.