How to make high quality cc and use the HQ mod?

I asked before about how to make high quality clothes and I thought I solved it but I didn't. I'm saving my textures as high resolution like 2048 x 4096 but when I put it into sims 4 studio it lowers a lot and looks even worse in game.  

Someone suggested I use the HQ mod? How do I use that to make HQ meshes? Is there any other way? Sorry I'm very new to this!