I can only open app from App Store how do I get the app back on screen

Use App Library to search the app you are looking for, see this Apple article:

Organize the Home Screen and App Library on your iPhone

https://support.apple.com/en-us/HT211345

Find the app in the app library on your phone, long press on the app you want on the home screen.

Long press until a pop up message appears with a few options.

One of those options should be "add to home screen"

Click OPEN.

Then you will find the app in App Library.

Tap on the app, drag to the Home screen & drop it.

OK, thank you.

Use App Library to search Jet2holidays app.

When you find it, tap on it (don't open it) , then drag to left to the Home screen & drop it.

Try again.

Strange . . . . ., an app from the App Store that opens a website.

Can you tell us what app that is?

Strange, take your time and try again.

That should work.

Try tomorrow again, drag to left to the Home screen & drop it.

May be ask a friend or family to do it for you?