3ds Max :: Remodeling Single Object For Use With Animation

I am new to 3DS and modeling in general. I am interested in getting into the programming end of game design and was hoping to get decent at working with animations in the process. I have downloaded tons of fantastic models/scenes, but all of them are single objects and that makes animation difficult. Primarily, I am working with biped models and need to be able to move their limbs independently and faces where I need features to be able to be moved simultaneously in different ways.

I have looked up tons of tutorials and have the concept of how to move independent objects through the time frame, but I have no clue how to take a single object, break down its components, and use them individually while still having them be linked. Again, I know how to make simple objects and join those objects at pivots, I just seem to be having trouble working backwards.

I tried working with the object as editable mesh and had trouble getting all of the wires into objects and maintaining any sort of realism in animation as things seemed to be willing to go all over the place (having done a bad job at attaching the mesh into good objects), is there a better way than clicking and dragging and hoping you go everything you needed without things you don't?. I was hoping there was a way place pivot joints within your model and then connect those pivot points with bones.

where I could get prefabbed scenes with models created specifically for animations. I could be missing something completely here, but there has to be a way to animate individual components of single objects, or else the purpose of having single object models is lost to me .