Mod/CC Creation

So, to actually reply to the OP instead of continuing the accidental hijacking of their thread...

In general, the way to get started with making CC and mods is to check out beginner tutorials meant to teach the first steps in doing whatever kind of creation you want to do, follow them and see if the stuff you make works, and then repeat the process with additional tutorials to keep working toward the end result you want. 

Depending on what you want to do, however, it may also be necessary to learn some things about how various aspects of the game and/or different kinds of content actually work... but that process isn't necessarily so different from the first process as long as you're actually thinking about how things work as you read/watch and learn.

(It may also be necessary for you to learn non-Sims-specific skills -- very likely using non-Sims resources to do so -- that are needed for the stuff you want to make, e.g. if you have no idea how to use Photoshop, GIMP, etc. at all, then odds are you'll need to learn things that CC-making tutorials alone can't teach you if you want to make anything but very simple recolors of very simple textures.)

If what you want to make is an actual game mod of the type that adds new interactions to objects (new or existing) and/or Sims, adds new game mechanics, significantly changes how something works, etc., then whether you'll find tutorials that will teach you most of what you need, or whether you'll have to do a lot of self-teaching on top of whatever you find, is going to depend a lot on what you want to do. That's one of the places where learning how things actually work is vitally important in order to know whether something is even plausible, let alone how to go about trying to do it.