One thing to watch out for on such an old bike is that you may not be able to get replacement parts for it if they are needed.
I'm servicing my Specialized Rockhopper which was built around 1992 and I need to renew the gear cassette due to wear.
Easy enough but for the fact that it's the original Shimano ultraglide system which was discontinued yonks ago!!!
As well as buying a new cassette I also have to change the rear hub to a Hyperglide to bring things up to date - so much for a cheap, inexpensive tidy up!! LOL!
As has been said, by the time you buy cassette removers, bottom bracket remover tool etc and if the wheels need truing, you may be better off getting a bike shop to do the overhaul unless you are going to use the tools regularly Good luck!
But you still need some tools, bottom bracket removal tool and the sort depends on what type of bb you have, cassette removal tool along with a chain whip. Take the bare frame to a decent bike shop and they will be able to get it painted properly for you.
Good luck, or why not buy a new one .............?
Decathlon do a kit with everything you need for twenty quid.
Chain Whip, Cassette remover (depends which it has), crank stud extractor, Bottom Bracket too, spoke key, chain splitter. I do all my own maintenance and it has stood me in good stead, bikes are a doddle.
I was saving up as a kid for a Raleigh Record Sprint and was doing quite well but my dad thinking he was doing the right thing got me a Peugeot racer off a mate and it just wasn't what I wanted but his plan was not just for me to have it, bought some choice bits from the local bike shop. he sprayed it and wrote to Peugeot and asked if we could buy some decals, they sent a set gratis, we chose a Ford medium metallic blue and with the red and yellow graphics it looked pure factory, Iscaselle turbo saddle, alloy rims it looked fantastic and cost me half what the new bike would have cost, so as has been said, get the decals otherwise it will look unfinished.