Clothing help

Hey Blender folks…

I’ve recently started using Blender and have found this site to be great assistance, so I come with a question.
I have an exported human model from Makehuman, and a shirt I’ve downloaded somewhere else. When I watch multiple tutorials trying to set up the physics for cloth/colliders I do it perfectly, but it still ends up going strange. I’ve uploaded the file so you can take a closer look at what I’m doing wrong.

I’m not sure if it’s a pinning thing, or something else I’m missing.

Any help is greatly appreciated.