It takes about 20 seconds. Then it opens like an app: book in two taps, and get a reminder before every session. No App Store, nothing to pay.
These pictures are from Safari on a current iPhone. Looks different? See the help at the bottom.
It's the round button with three dots, beside the web address.

It's the first option in the menu that pops up.

It's the round button with an arrow, at the end of the row of icons. Once it's open it says View Less.

Scroll down the list a little if you can't see it.

If you see Open as Web App, leave it switched on.
Illustration. Your screen will show your own icon.
Find the Padel Social icon on your home screen and open it from there from now on. That's how your session reminders reach you.
Your address bar may be at the top of the screen. Tap the share icon next to the address, then carry on from step 3.
Tap the share icon (a square with an arrow) in the bar at the bottom, scroll down, tap Add to Home Screen, then Add.
Tap the share icon in the address bar, then Add to Home Screen, then Add.
Scroll to the bottom of the list. If it's still missing, tap Edit Actions and switch it on.
Still stuck? Message Padel Social and we'll help.