www.sheldonbrown.com has a lot of stuff pertinent to older bikes. Some of it is for 40+ yr old equipment. The general principles for bike repair haven't changed much but if you are not mechanically inclined it can be a bit hard to make sense of some of the older stuff with only newer equipment writeups. www.parktool.com on the L side has a lot of repair info, mostly oriented toward bikes less than 15yrs old but they do have info pertinent to older bikes. It does assume some familiarity with what is old and what is new. You will need some basic tools and some tools unique to bikes of that era for best results.
Parks and Pedros make good tools.
Try an Amazon or www.abebooks.com search for the Richards book, or Zinn's book on bike repair. Steve