Make sure you get a board that fits you, based on height and weight. This depends on your tastes, but I am 5'7" and I ride a 154cm board. This will go up and down in height with park riding or if you are out west in Canada riding deep powder you want to have a longer board.
Pretty much you want a board that is right around your chin when you are standing straight.
Step 1: Getting a board that works for you , and rules of the slope
Get a board you feel comfertable with. I suggest you rent a board for first time. Take a lesson from a paid teacher on the hill for your first time to add to the experience.
Also, no matter what, you will fall ! Do not try to learn too fast, you do not want to hurt someone on accident. There are key things you have to know before the first trip down the slopes. They are :
1. Always stay in control, and be able to stop or avoid other people or objects.
2. People ahead of you have the right of way. It is your responsibility to avoid them.
3. You must not stop where you obstruct a trail, or are not visible from above.
4. Whenever starting downhill or merging into a trail, look uphill and yield to others.
5. Always use devices to help prevent runaway equipment.
6. Observe all posted signs and warnings. Keep off closed trails and out of closed areas.
7. Prior to using any lift, you must have the knowledge and ability to load, ride and unload safely.
Since this is HOW TO SNOWBOARD, each of the following things are explained in this instructable.