Slowly, so as not to complicate things
First learn to walk, then run

@joebloogs
First, why do you need a skin? NextGen is much richer in functions than Primo. For the vast majority of standard users, they don't need anything more
Also, if you only need a few more functions, you can simply add them by inserting the relevant ux files.

I would advise you to make a good classic package (for example the PAL, directions from the tutorial), familiarize yourself with all its features, and only then see what you need in addition. Or specify immediately so we can direct you
Only after that see if you need to use Arimi, Garigor, Pongo, Frontzosd or Wandel skin ...