I'd tried the tempered glass screen protectors but with the otterbox case my phone lives in they didn't stay on the screen.
This was the alternative.
Using the cloth provided give the screen a good clean. I used some lens and visor cleaner to apply... sprayed some on and then got the screen protector in place.
With the help of the cleaner (or other suitable lubricant) you can move the screen protector into place.
The kit also comes with a squeegee so use that to run the lubricant out and clean up with the cloth.
Sticks really well and so far seems to do a good job of protecting against any scratches