Trying to build a pool,and not able to,help

havent tried to built anything yet just getting started again after a long time away, but is the lot/ land where u are trying to build is flat, hilly,etc.  is so maybe needs to be flatten out first to build. like i said just getting started back in game getting babies right now lol.

Sure you know a pool needs 3 x 3 squares. Do you possibly have a basement below the place you want to build the pool? In this case you can’t build a pool there.