I was asked by a teacher how to bring the arms into play with her students. Arms can often feel separate to the rest of the body especially to beginners. What is important here to to help them feel that the arms are a part of the whole, because they are.
A way to do this is to create a direct connection to the movement of the Navel. I do this using the elbow.
Bring the arms up to heart or throat height or whatever is comfortable, that does not pull one out of alignment. Proceed by creating a connection between the Navel and the Elbow: If the navel move out so does the elbow, if the navel moves in so does the elbow and so on. keep the wrists and hands soft as possible so that they can simple follow. Also keep the should and upper arm connected and in mind, as the shoulder rotates to facilitate to movement.
you will begin to notice that this affects the movement quality of the whole body. Dont forget to breath, keep you jaw soft and stay connected to the ground. If you loose the connecting you will notice that you will probably loose the flow and ease, just keep returning to it.