I've done a fair bit of boating either on rentals or on other people's boats.
I got my license a couple of years ago which goes through a lot of the safety and rules of the road type stuff (weirdly, you can rent without a license in Canada, but have to be licensed to operate a private boat). I've been reading back through that to make sure I'm familiar with the basics. That said, it misses a lot of stuff like boating with kids or docking on anything that isn't a nice big straight, flat chunk of dock.
I'm also hiring an instructor starting next week, but he's a marine biologist uni professor, so not quite sure if it's the same as a safe boating or power squadron type course. We shall see.
First trip out was interesting. Ten years since I've started a carbureted engine, so I forgot that it wouldn't just start by turning the key. Then, I've never pulled into or out of a marina slip, so that was an adventure. Fortunately, my friendly neighbour was there to "catch" me!