More than likely, your level of interest in this dispenser directly corresponds with that of your cat for food, so it'll probably be very easy to train your cat to use it. Here's what I did:
1. Fill the tub at the top of your feeder, but don't pack it to the top, or the pellets will be wedged in place. They need to be loose enough to easily spill through the baffles when your cat bumps the feeder.
2. Put some pellets of food in the back of the feeder's base, so your cat will have to reach up inside with his paw to get them. During one of these food-reaching endeavors, the feeder will probably get bumped and a learning event
3. If your cat doesn't seem to be getting it, try bumping the feeder yourself to show how it's done.
4. Make sure your cat's getting enough to eat by opening the lid and checking the food level. Put a limited amount of food into the base of the feeder each day -- just make sure your cat will run out at some point during the day, so that he'll have a reason to try to get the pellets in the tub.
5. Let nature take its course! Your cat will take a few weeks to get good at manipulating the feeder to drop pellets. Yoshi gets a refill once a day, whether he needs it or not, and we still put a few pellets into the base, just to give him the satisfaction of knowing he's been fed.