An alternative might be to buy an olf Raleigh 3-speed. They can be had for a song, and when you finish your restoration, you have a pretty cool old bike for doing some alternative-style rides. Granted, you won’t get the experience of working with derailleurs, but you will get to do the bearings (including the oedals), cleaninf (which is almost an art itself), and working on internal hubs. There are lots of videos for proceeding with any bike, but I’d start with an inexpensive one and donate it when finished. Whatever you choose, you’ll learn a lot and have a lot of fun. And a tip: keep a bottle of Dawn dish detergent and a 3M scrubbing pad next to your work sink - you’ll get dirty.