I started with a buddy of mine. So he had most of the gear that was needed. I just needed to buy a gun, do hunter safety, waiters and some camo.
Now if you're not in a situation where you have someone who already hunts you might need to do a fair amount of local research. The basics you will need are what I had to buy a gun, waiters, and some camo. With the waiters you will not need a dog right out of the gate. My buddy and I still don't even use a dog.
The next big problem is where to hunt. This you will have to figure out locally. Where I live we go to public land that requires that you have a boat to get to a good spot. If you have private land you can scout it out for where you see ducks and then you could setup there. You also might be able to find public land that you could park your car and walk to.
With decoys we started with buying a 12 pack of whatever ducks you have locally. Early season we tend to use less decoys because the duck travel in smaller groups and then increase as the season goes on. So later we bought another 12 pack of mallards which are the late season bird here.
The best resource I found while starting is the Ducks Unlimited website. They have a good amount of resources on decoys, calls, guns, and just about anything you will need.