@Stctp03 first of all, you'll need this: https://booth.pm/ja/items/7657840
just drag it into your project, then go to Tools > MochiFitter and install the Blender bundle. It’s a pretty much beginner-friendly and intuitive tool, some outfits may still look a bit weird, but it's definitely helpful anyway.
upd: if you imported the profile and it doesn't show up, just reload the project
Here is some guide https://youtu.be/1PzYYylFMlc