start at the lowest point of learning. What makes stuff work.

e.g. basic power and ground to switch on a lamp, now add a switch to flick it on and off - now remove the switch and add a relay to that circuit so you can remotely control it from another switch placed where you want. (relay is basically just a remote controlled switch that allows a lower amp circuit drive a higher amp consumable (e.g. condenser fans)

Im sure you will learn a lot just by understanding these concepts, you can now get into solenoids which are nothing more than coils creating magnetic fields to move a metal slug to do something (usually open or close a port).

once you are bored of the above, get into position sensors - two forms are used a lot the variable reluctance sensor and a hall effect sensor, both are used to identify an "event" on a wheel/slide/position of something from a prefabricated tone ring. (crank and ABS sensors on most cars)

get yourself acquianted organically. Its the best way to learn.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)