well no one can really teach you its more of an see/experience type thing. First you should pick the brand or market your interested in the most such Japanese, american, european. Then just look around online search for the specific cars your lick read all the info you can, watch videos, look at different possible set ups for that motors in each. Eventually you will know what is the right way to do things and the little quirks of each one. As for me im more of a JDM kinda guy and there are a lot of different avenues to go down whether you want to know JDM parts or just aftermarket then you got the brands and the specific motors such as RB26dett, RB25det, 2jzdett, sr20det etc. those are the most popular. But yea just keep reading and taking in as much info as you can ive made a folder of things ive found that i like so i can go back to it and pick and choose what i want to buy later on.
good luck