I know the basic components of a car and how they work in general, but when it comes to repairing or replacing specific parts I wouldn't have any idea where to start. It's obviously not like a computer where you can more or less buy a case, hard drive, RAM, etc., put the square plug in the square hole and the round plug in the round hole and it works, and you can't just mess around with your engine and if you screw something up, reformat, and you're back to where you started.
So I'm wondering if you have any suggestions for where to begin learning more about the internals of the engine and other car systems without making it a full-time job.