Legs with race skin

Hello, I am not entirely sure where to ask for help exactly.

For starters - I know more or less about Blender, 3ds Max and similar for 3d modeling, I know propMasks and how to add custom clothing to server, my only problem is figuring out how to actually make pants with visible legs, like shorts or long pants with slight legs visible for some default shoes.

I am trying to figure out like what specular texture I need there, what normal texture I need there, or even what vertex color is going there? How do I make any of my pants with legs work?
What if I want to make a pants where only one leg will be visible (its a style!)?

Maybe I am missing something? Is there a thorough tutorial about it?

there are a lot of videos out there to help, keep searching and keep mucking around with things

This video does not even explain anything about creating actual clothing with skin texture and UV mapping of that skin, so it is completely missed the question.

I would not otherwise ask if there was a clear video/topic about it

again, there are Plenty videos out there, that video is a simple starter one that can be useful either way.