I just bought a Raleigh Capri bike from the 1980s I think. It was made in Taiwan. Anyway a big problem I'm having is that I decided to do a little cleaning up of the bike like cleaning the chain and the drivetrain and lubricating the parts. Well one thing led to another and I took the thing apart so much and can't put it back together. The rear tire is off. The big thing is I think it's the rear derailleur that I disassembled to clean and cant figure out how it goes back on. It's a Shimano Tourney but is really old and doesn't look like the new Shimano Tourney I see on amazon. Also the chain I couldn't get off. I was looking for a master link one but couldnt find it. It also looks like the metal cables are kind of rusty and stiff and may be a good idea to replace those. I've been looking around for videos to help me out but I feel like I have ancient equipment and none of the stuff the videos show looks like what I have. Can I get a new rear derailleur or do I need one and a new chain? Or are there videos that show step by step? Or should I just take it to the bike shop and ask them to put back together? I wanted to get a cheap bike first so that I could learn on it before getting an expensive bike. I didn't realize bicycles were this complicated when I started taking it apart.