True First Person Single Mesh Controller Setup

I’m looking to create a true first-person character strictly with one skeletal mesh as seen in this video here:

I’m wondering how I can replicate this, specifically having the arms locked in front of the camera while the shoulders maintain the position from the full body mesh animation. Being able to see the shoulders is really cool as well. This will help me focus on creating the first-person hand and weapon animations while having them blend with the animated body seamlessly.

Where can I learn more about this type of implementation? Any suggestions would be greatly appreciated.