For mommies who have homes with stairs... teaching your baby about the stairs being dangerous?!?

We recently bought a house and will be moving in the next 2 months.. we have a 15 month old who is learning to walk. He's also very rebellious and when we say "NO" he only wants to do something more and laughs at us if we hit his hand.lol... anyway we are moving to a duplex and I'm just so scared of him with the stairs... I plan on getting baby gates but how do I teach him that's a big "no-no" without him trying it anyway just because I said no?