So sorry, its kinda NSFW, but can you help me?

Once again, so sorry if its kinda NSFW or awkward. But i can’t seem to understand this problem. I’m also just a beginner. So please, if you have time, can you kindly guide and help me?
I recently created sims 4 adult clothing. I want to edit this outfit


And i already managed to make it like this

But from here, when i upload to Sims file studio, it looks like this
Untitled 3
Can you guys help me figure it out, how to make the texture looks like the second picture. Is it hard to do it?

It looks to me like maybe you just hid the original dress mesh. HIdden meshes will still be exported for all the exporters I know of. You need to remove it or select only the meshes you want to export and check the Selected Only checkbox when exporting.

Hey, you are right. I use sculpting mode and use pinch or grab mode to pull the lower parts.