Don't wear jeans. You will be spending time on your butt, your jeans will get wet and you will get cold. In a deranged, hypothermic state, you won't be able to mouth your favorite expletive. On your feet, wear one pair of medium weight or light weight socks. The fit should be snug, and your heel should remain in place when you bend your knee and ankle forward.
Most snowboard clothing is designed to fit looser than ski wear, giving more freedom of movement.
Also, many snowboard pants are reinforced in the seat and knees for extra protection when kneeling or sitting on the snow. Take a Lesson First-timers should take a lesson from a qualified snowboard instructor. It's the quickest way to learn and will save you some bumps and bruises. When you get to the resort, head for the snowboard school where you will find information about programs and lessons. Once you learn the basics of sliding on the board's edge and making the turn, you will probably find yourself getting very comfortable on the board.