Okay so I have been searching youtube all day and I still don't know how to create my own custom content. Can someone help?

Have you looked in the Tutorials or Tools forum? Also, what kind of content do you mean?

I have looked but I got really confused, and I mean like sims 4 clothing, accessories, and all that happy stuff. I need someone to like message the steps to me and what I need for it.

If you use Sims 4 Studio to create your clothes and accessories, they have lots of easy to understand tutorials for making CAS items on their website. Take a look through their CAS tutorial index.

If you are going to make new items (new meshes), the simplest way to get started would be with their very basic tutorial on making a pair of earrings, here: http://sims4studio.com/thread/10/tu...tudio-accessory. Otherwise, if you're just doing recolours and not new meshes, then just look through the tutorials that are to do with recolouring.