Hello, first post here. I hope if you help me it won't be my last...

A friend has given me an old Rayleigh road bike. It's night time now, so you'll have to wait til tomorrow to see a picture of it. However, it currently doesn't have any gears and they're something I'd prefer! It's got a rear cogset but no front/ rear derailleur. I'd prefer to just restore the old gears instead of just putting some brand new ones on, but I don't really know how hard it'll be...

So, just how complicated will this be? I've read a couple of articles on the net and it's made me realise I know barely anything about bikes. Would it be hard to the parts for such an old bike?

Thanks in advance!