Every automotive circuit in these old cars is the same basic idea. Either Battery->Switch->Component->Ground, or add a relay in there. If you stare at enough of the diagrams and trace out a single component, you'll realize that auto electric is super easy. For modern cars, switches go to relays, typically of a solid state variety in a body control module, power distribution module, etc - whatever that manufacturer decides to call it. It adds a lot of wiring and complexity, but allows you to do some nifty things like "allow the user to roll down the windows for 15 seconds after the car has been turned off" or "use your radio to turn down the A/C". There's a bunch of other cool things you can do with the modern setup too, such as disable/reverse the passenger window if the current draw is too high (because a kid has their head stuck in it) or turn off the left headlight while the left turn signal is engaged.
But that's not what you asked. You asked about courses and education. I joined HP Academy, and have been very happy with their courses. I recommend watching some of their youtube videos to get a feel for the teacher, 'cause he's not for everyone.
Here's a good one to start with - just skip forward until you get to the teaching part.