Did you get a home inspection? Start with the things on that. If you didn’t, then start by reading up on home inspections, and start taking care of those things.
We did get an inspection. I can’t rave about our inspector enough he explained in detail which was helpful but a tad overwhelming. We are trying to get a contractor out to quote on the siding (it’s original in 1987 house in humid area) but I’m struggling with some of the inside stuff that I know I can handle.