I wouldn't say real life electronics experience is needed; I hadn't had any when I built the computer in the first save you linked. A good understanding of basic integer math should be enough.

To give you a personal example, the first ever logic circuit I had a hard time designing on my own was the adder, so I looked adders up on google and guess what, I found complete circuit diagrams with explanations for those with no electronics background and... a lot of snakes! (Here, have a good article on adders. The binary kind, not the snake kind.)

OK but you should read the comments and enable deco btw.

Hey, it's not my fault, the author of the save forgot to put a sign there to remind people that deco should be enabled :P My saves always have such a sign.

It probably didn't take more than a grand total of about two weeks of active development, but it was spread out over months. I didn't use any specific "method" of electronics as this is not strictly electronics, as I've already hinted a few comments earlier.