Seek permission from your local building and zoning authority before you start to dig your hole. You'll need to satisfy local building laws and apply for permission to carry out the work in most states.
Select the location of your in-ground pool. Choose somewhere that's going to get plenty of sun for most of the day. You should avoid digging your pool into low land. Pools sited in low-lying land can be prone to flooding.
Ascertain the dimensions of your in-ground pool base. You should have been given these by your pool base's manufacturer. If you weren't, you'll need to measure the height, length, and depth of all sections of your pool as accurately as you can.
Dig your hole with an excavator. If you're not licensed to use an excavator, consider hiring a contractor who is to assist you. Digging the entire hole by hand will be a long and drawn-out process. You should regularly measure the depth of the hole you're digging. Use a spade to add and remove earth accurately as you work.