Hayward Over The Wall Mount Skimmer

So i bought this to try it out and we love it.
Hayward over the wall mount skimmer. It includes all necessary hardware return hose fitting and vacuum adaptor. It is durable rustproof and has high impact abs resin construction. The basket pulls out for easy cleaning and the durable plastic material is not affected by pool chemicals. The bestway pool surface skimmer is the best way to clear debris from your above ground pool and hook the surface skimmer over the wall of the pool right near its suction inlet.
The skimmer easily mounts to easy set or metal frame pool sidewalls with an adjustable bracket and attaches to the filter pump for automatic skimming. Intex deluxe wall mount surface skimmer help catch leaves and debris before they sink to the bottom of the pool with the intex deluxe wall mount surface skimmer. Functionaloc pool surface skimmer for above ground pool wall mount swimming pool surface skimmer automatic skimmer for pool daily care 25x25x32cm 4 5 out of 5 stars 2 69 72 69. I m confused on whether i need to cut the hole first and then put the.
I get that the gasket opens up to fit on both the outside and the inside of the liner. We are installing a through wall skimmer in an intex 9 x 18 rectangular pool. Lomart standard over the wall skimmer is and above ground skimmer. Feel free to ask questions.
It s a hayward sp1091lx skimmer with a butterfly gasket. Mount on the pool wall to suck floating leaves or other debris. I really did not want to cut a hole in the side of the liner. High impact abs.
I m confused on how to install the butterfly gasket.