Get yourself a Gregories service & repair manual for a Datsun 1200 [try eBay] they are cheap & are writen for the home maintainer.
They have lots of photos showing how things are done & should be one of the first things you buy whenever you get another car. They will save you a lot more than their purchase price with the first screw-up that you DON'T make as a result of reading it twice & fixing it once.

For what it's worth, I've been a mechanic all my adult life & I have a book case full of Datsun manuals. Real mechanics DO read the manual when necessary despite what some backyarders might tell you.