First off, it doesn't matter that much. You could be riding your grandpa's junker board and totally crush the jerry who dropped $2000 on a top of the line setup. What matters is getting out there and riding, and getting feedback on your riding.
Ok, so you're still going to buy a board. Great, read on.
Figure out your riding style.
Do you want to ride fast groomers? Trees? Park? Powder only? Some or all of the above? What about switch? These choices determine the length and shape of the board. Go with twin if you want to ride switch, go with a longer board for speed or a shorter board for maneuverability.
So, you've found the shape and the length of the board. The last one is waist width. This is primarily based on skill level and your boot size. Narrower boards are easier to ride, but you can't get as far on edge when carving. If you're an advanced rider with a size 13 boot definitely go ultrawide (27.5cm+).
Ok, that's it. All the other stuff is fluff: what really matters is finding a board and brand that speaks to you, and that you're excited to ride. Then get out there and crush it.Search Snowboards