Start with watching the "how to build a deck" vids on YT. Go through https://www.decks.com/
Analyzing what my dad built at the house I grew up, you aren't going to need anything expensive. A tape measure, good saw, nailer or screw gun, level, square and string is pretty much the tool list you'll need.
Concrete block footings, 4x4s, and 2x10 joists/beams, and 2x4, 2x6, or cedar for decking. If budget allows, plastic wood is a nice option. It's unforgiving if you make a mistake, though.
Build the deck around the pool in a square U shape, leaving a ~4' empty space where you can probably just build a platform leveled on concrete blocks (pavers) for the step. Wrap the base in lattice or planks to finish.
I built a basic 12"x12" ground-level deck using pavers for footings and 2x4s with 1x4 cedar decking. Tired of dealing with the s**t grass/weeds that never went away around the septic lids. I cut out access panels so the septic tank could be inspected yearly. If I needed to, I could lift the entire deck up.
We had an 8' stock tank pool at our old house (I called it my wife's Pinterest Pool). We ran an Intex (sp?) filter on it, and I got an inexpensive propane on-demand water heater. One 20lb propane tank took the water from low 70s to 104*. And it skirted the HOA, which requires permits for pools deeper than 24".