I have done two conversions myself without much electrical knowledge, Have you got a treat in store for you! The very first thing you need to do is to get a (schematic diagram). That could be a major undertaking in itself. I doubt anyone could help you much without that at this point. Google it and it may come up. There are no shortcuts. This is going to be very difficult, but well worth it in the end
I have done a Magnavox phonograph and a Newcomb PA conversion. The more you find out things it seems the faster you start understanding until the whole thing starts to make sense. Anyway I will leave you to ponder that!