Help with wiring and electrical components

I'm new in the game, i've start playing yesterday actually and I've liked the role of the engineer so, have a lot of doubts about the wiring and electrical components stuff like if they work or not (or if it's worth it or not to put them) in the already existings submarines (we play in the Vellamo) and how to make them work. I know nothing about the signals and wiring things that weren't explained in the tutorial :,( so I was searching for a guide about this stuff or something to help me out with this but i didn't find anything that could help me to understand it so i hope you can help me with this becauase I've found it to be a very fun thing to do while nothing is happening on the submarine.