A proper beginner surf board posture is different from the stance of most intermediate advanced surfers. Beginners need to balance differently to ride foam waves to the beach.
An advanced surfer will catch the face of the wave and bottom turn into the pocket. He will look like he has his butt over one rail. He is riding face side or back side to keep the rail into the wave. A beginner is riding straight on a foam wave.
The Beginner Posture
The beginner surf board posture is the front foot across the stringer in the middle of the board with hips and shoulders squared to the front, knees flexed, and hands out in front of the board. This keeps the surfer’s body equal on both sides of the stringer that runs down the middle of the board.
In this posture, the board will run straight and the surfer does not have to move much. Once the beginner lets a shoulder drop back and one hand trail body, the hips turn and the butt sits over one side of the board. This causes the board to tip and the surfer to fall off the back.
The pop up is where the proper riding posture begins. In an advanced pop up or the beginner pop up I use, the hands stay in front the total time and this keeps the shoulders and hips straight
For a dry land demonstration and in water demo see my video.
For a good video on catching waves