Product Viewer Template- Exploding parts

I see the Explode BP, and the controls when I add the BP to the scene. I just can’t figure out what or how to attach to the Explode BP to make parts explode. I’m very new to UE4, and have extensively studied the Event Graphs that Marc showed at Unreal Academy, but it’s difficult to understand. I tried to take notes, but didn’t see how he made parts move and explode. I can’t seem to ever get the “Explode” button to show up, even though I see the Widget. Sorry for being a noob.

I really see the huge benefit of adding interactivity, and really do see that UE4 and realtime rendering is the future for interactive CAD visualization.