Happy July 4!

The skimmer is mounted to the wall and the return fitting installed, right? If not, get them on quickly!, they have to be in place to cut the liner. Before cutting the liner, the faceplates need to be screwed on. As long as the liner is tight to the wall, there is enough water in the pool to do so, if the liner isn't tight to the wall and you install the face plates you could end up with a wrinkle. Once the plates are on take a new razor knife and cut along the inside of the plates to remove all the liner - it's important to get a good cut on the return or you'll have trouble getting the eyeball or a plug in or out of the fitting.

HTH - enjoy the new pool!!