The first thing you need to do is drain the pool. This can be done in a few different ways and differs depending on the pool. You can use a sump pump or connect your pool vacuum and turn the pool filter system to waste and it will pump out the water.
You could use a garden hose and siphon out the water. All you need to do is submerge the hose completely in the pool, completely filling the hose up with water. Now, place one end out of the pool and on the ground. You can use multiple hoses if the water removal is taking too long. Each process may take several hours, so make sure to check on it from time to time.
There may be some water pooling on the liner after using the sump pump. You can remove the remaining water with a wet/dry vac or just grab a bucket and scoop out the remaining water.
Before emptying the pool, check where you are allowed to drain the water. Check with your local city council to verify where you should dispose of the used pool water.
Remove the Liner By Cutting It Out
Cut the liner with a razor knife at the base of the wall all the way around the pool, and under the pool step. Then cut vertically from the floor, up through the top bead in several places around the pool. Carefully pull the liner out from the track by lifting it up and outwards, the plastic track may be brittle and can crack if stressed. Roll-up the wall sections, and remove them from the pool. Leave the floor section of vinyl liner in place, for now, keeping it in the pool until you are ready to work on the floor.
Carefully remove, with a large size 3 Philips screwdriver, the faceplates for the skimmers, wall returns, main drains, pool lights, and pool step sections. You can use a cordless drill as well, but be sure to use a large size 3 Phillips screwdriver.
Safely store your screws, so none get lost, you can use Zip bags to put the screws into. The screws will not need replacement if they are not damaged or rusted. It is however recommended to replace the faceplates and gaskets, except for the step gasket, which is a very thick and durable rubber seal.
Seals You Need To Get When Replacing Your Pool Liner
Order the correct gaskets (they differ by Manufacturer) for your skimmer, main drain, pool light, and wall returns. There are two gaskets that are used, one behind the liner, and one on top of the liner.
New faceplates for the skimmer, drain, and returns are also recommended, as older plastic faceplates will warp and crack, which makes a poor seal that can seep and weep water.