1. Place your hammie on a stair.
2. Wait patiently.
You'll have to wait for a little while for this one. Hammie will walk all around the stair for a while and finally realize there's no way out except up. He'll then stand up leaning on the stair. To temp him, get one of his favorite foods and hold it on the stair just above his head. Eventually, he'll dig his claws into the carpet and drag himself up. Reward him! Now repeat the process until hammie can climb the stairs with ease! (Buttercup climbed 14 stairs once!)