One thing that you want to think about when drawing is how foreshortening works, It allows you to give depth to your drawings. Think of a cylinder as it moves towards you, The closer end gets larger and larger as it "falls" to you
This idea works with an arm, as the arm gets closer to you larger parts of the arm overlap smaller parts, so you don't see the smaller parts that would be hidden
With this idea in mind the overlaps then create a T where they overlap the part that is further back in space, it gives you a better idea of how to then build foreshortening back in space.
