How to i get into building/tuning cars

So ive been wanting to actually build cars for a while but i have no clue 1. how to even build cars correctly i just pick the thing that sounds the coolest but i want to actually find out what things do and 2. i want to know how to actually tune cars but i know what like 2 things do in the menu any help would help a ton

 

You mean a base game car? Just click esc, then at the top go to vehicle config, and it will open a new menu to modify your car. There are sub tabs in that menu to switch between parts, tuning, etc.

 

are you referring to designing cars in automation, or using the configuration menu in BeamNG?
in either case, the parts are the same as real cars, you can find a lot of general information with a quick google search on the specific part.