Animating Custom Armour Models?

I have made a custom armour model in BlockBench which covers the arms and legs of the player model. I have taken these parts and have attempted to set animations for them when importing the .java file but when I try it out in the test environment, the arm and leg pieces just stay in place while the player swings their arms and legs while walking. How do I animate the model to move with the swinging arms and legs?

Please answer ASAP

Thanks