How would one add muscles to the upper body of the unscaled version of the LaiUlrich2022.osim model?

In particular, I am integrate the existing Upper Extremity Kinematic Model (https://simtk.org/projects/up-ext-model), which contains a .jnt and .msl file. Thank you!

Will I be able to capture video that has obstacles or obstructions? For example, capturing the video of someone operating a hand-powered wheelchair with part of the arm obstructed from the camera at times.

Thanks!