Confused noob here - Rigging for UE4 w/ Blender

I have a set of armor, and I can throw parts of it into UE4 and apply them to an existing, animated model and tell them to follow that model’s animation blueprint, like in this video https://youtu.be/bE0g_djR12s?t=9m44s. However, even though they are weight painted and have their own skeleton, they still don’t move at all. Is this because I don’t have any “controls” in Blender? In this video he seemingly just exports the mesh and skeleton, I’m quite confused.

Is it even necessary to make controls in Blender if I’m only planning to retarget anims inside UE4?