The guy in the video just deleted the left hand half of the shape to be able to use the 3D Revolve effect.
Dunno why he uses the shape builder to do so. Shouldn't be necessary.
Basically all you have to do is to draw a circle, then drag the bottom anchor down to make the thing egg-shaped.
Then delete the left hand anchor and go to 3D Revolve.
Yes that tutorial kind of annoyed me as well, it is a good tutorial but not turning on the poreview while mapping art might not be the most efficient way of going about it.
this is to show you how easy what Steve wrote is actually to achieve by comparison to what was shown in the video.