carnauba was works very well on dark color car. but only soso on light color car.
i have a silver car, i usually go to touchless car wash to wash first. then use bugs and tar remover if necessary.
first time, use polish+wax product. cover that with another layer of wax.
i use only "easy on and off" products. and i will also look for "no white residual" products.
use clean microfiber to wax and remove wax. wash those tower with wash machine after each use.
when wax, use front to back motion instead of circular motion. (circular motion is the reason for swirl mark, if you use front to back motion, even if there is scratch, it will be less noticeable)