What I can remember, and it been a few years since swimming there, you have cubical that you can change in, not a communal changing room. They do have larger family cubical are available as I've change in there with my wife who is wheelchair bound and her large wheelchair fitted in their.
I've showered in the showers using my own shower gel before now.
The F&B shop is very open, with seating by the pool.
I hope this helps