|Overlap style liners are installed under the top rail of the pool. To install an overlap style liner, the top rail of the pool is removed all the way around the pool. The liner is put in the pool, and draped over the top of the walls of the pool. Long plastic clips go down over the liner and the top wall, holding the liner in place. The top rails are then put back on the pool, and the excess liner hanging down on the outside of the pool is trimmed off. If you have an overlap style liner, you can look under the top rail on the outside of the pool, and you will see the liner hanging down.