How to choose a snowboard
Figure out what type of terrain you want to ride
Do you want to do jumps in the terrain park/go out do jumps off natural features/ride steep terrain?
The most important factor in choosing a snowboard is to determine where you spend most of the day when you're snowboarding.
Whats your current weight? Your weight would affect the length of the snowboard you use
Are you a beginner/expert rider. Its recommended for beginners to use snowboards which are made of softer materials so that you can initiate turns easily when you twist the snowboard.
You can talk to the assistants at the snowboard shop as most of them ski/snowboard and would have good advice.