Need help setting up Just Fit Breast PB.

[KastIronBriar]

As the title states, I need help getting this set up. I have Modular Avatar and VRCAvatars3Tools but I'm not sure what to do with either in this situation. The steps listed by the JFBPB creator aren't detailed enough for me to follow. If someone could take the time to make or share a detailed explanation of the setup process, either with a video, through screenshots, or a written step-by-step list, that would be greatly appreciated.
The avatar I'm using is Lasyusha if that effects anything.

[Rolbin]

did u know how to manage it? am rlly struggling with it.

[Ghost 0]

I used this video: https://www.youtube.com/watch?v=ZVEpd-RuUYQ