Hi Linda, here's a good article all about how to build a pool deck: https://www.popularmechanics.com/home/how-to-plans/how-to/a174/how-to-build-a-pool-deck-easily/
If you’re talking about a freestanding swimming pool, that is above ground, I saw some free plans for this kind of deck work online somewhere. You might just google free deck plans.
I would Think about bare feet and splinters, think about wet decking, think about a handrail if it’s >24” above the ground.
You could get cement blocks and stack them