Remove grass and debris, then use a long level or laser level to ensure the area is flat. Spread and compact sand or a foam pad to create a smooth, even surface before installing the pool.

Adjust the leveling feet at the base or place heat-resistant shims under the legs. Use a spirit level to check.

Place shims between the frame and studs, check with a 4-foot level, and adjust until the door is perfectly vertical and horizontal.