How would I move/rotate body parts and keep them stationary?

So I have a pull-up bar (You know, the ones they use in the gym) in my game. How would I put the torso under the bar (This I have no problem with), rotate the arms to face upwards (I don't know how to do that part), and keep all the character's body parts stationary (I'm assuming you could anchor them, but that doesn't seem efficient...)?

I am not requesting a script. I just want the knowledge of some methods or functions that I can use, maybe provided with some links. I have absolutely no idea where to start.

In order to do this, you should first evaluate the children of torso. These include Right Shoulder and Left Shoulder. Rotating these rotates the arms, but from the pivot points.

You can do this by accessing the SetDesiredAngle method of the Motor6D.