How can I attach a crank like this to a motor like this?

Thanks for the tips. I guess a big question I have that I didn't explicitly ask is: how do you attach things to the motor shaft (or whatever the rod sticking out of it is called)?? It is totally smooth so it doesn't make sense to me how one would connect something. I would also love to just extend the rod like 8 inches (shuttup) so how would I do that? Do I remove the shaft that is already there and replace it or is there an adapter?