Mech Joints

I don't have basic knowledge on movements of vehicles. I'd like to know how to operate joints and animate them on a mech I working on. I have the joints done but I don't know how to make them moving joints. I want to set up the joins so the mech will crouch and the torso will move with the legs when I'm walking. The mech has boosting so I need to also know how to animate these parts in a press of a button when in use. Thank you for your time in reading this. I hope to get help on my project!