Baby Plinko

I found this cool toy for Zach that is like his own version of Plinko and a walker all in one. We sat down with it and the ball and I showed him (over and over) how to drop the ball into the hole on top and it will come out of one of two places.
I was watching him play with it on his own and his version of the above steps go like this:
Zach holds the ball over the hole at the top. Then he sets the ball in the spot where it should come out of the toy and lets it roll into the stop position. He figured out how it goes in and where it comes out, but he doesn't realize that it goes through the inside.