Rent a board. Don’t buy one until you are sure that you like riding.
Buy a lift ticket at your local ski area.
Look at the area map and find the bunny slope. Find out what lift takes you to the top of the bunny slope.
Get on the lift. Hopefully you will have figured out how to shuffle along with one foot attached to the board so you don’t miss the chair.
Once at the top of the slope prepare to get off the lift. Raise the chair bar and coast down the little rise at the top of the lift with your detached foot in between the two bindings.
Shuffle out of the way of the other snowboarders and skiers, and sit down. Attach the binding to your back foot.
Stand up. Or attempt to stand up. It may take a few tries. Once up, and if the slope is steep enough, you will begin to slide on the snow. Keep standing until you fall down. You will fall down. Don’t get discouraged. Bruises are part of learning how to board.
Remember that if your back is to the mountain you want to lean back on your heals. If you are facing the mountain you should lean forward on your toes. You want to keep on edge of the snowboard cutting into the snow at all times. This is how you control your direction. Switching direction involves the shifting of weight from one edge to the other. If you can do this. You can snowboard.
Get up, coast, fall. This is how you will learn. Soon you’ll be coasting more than falling. And after that you won’t fall down nearly as much and the black and blue spots on your body will begin to disappear.