everywhere does adult swimming lessions, small groups or 1 to 1.
I know nothing about the proper way to teach swimming but I did teach my kids by getting them relaxed in the water and used to putting their face in the water, going under, floating unaided, that sort of thing. Then when they got used to that it was basicly swim from wall to me for 1 meter, 2, meter ,3, 4, etc etc. Used a kick board a little. My perspective is the body floats in its natural relaxed state so its not that difficult.
Once they could do a 5 meters doggy paddle I taught them breast stroke. Getting the stroke right was harder than all the other bits put together. After that I taught them a bit of frontcrawl, then it was the swimming club.
One of them is national standard now 🙂