Hello Martin,
Great question. Given that we have created strength and leverage to the top of this motion, we have pushed back and loaded the ribs to the top, we are centered and balanced and the hands and arms are pressurized together with the body at a four or five, the surfing motion begins with the feet shins and knees in the (Surf the knees) movement. As we know while we are surfing the knees we are also pushing back into the left glute (for a right handed player).
In the Chapter 4 Support section (under the chapter support tab located below your training lesson), under the “Chapter 4 Assessment” at the 1:45 minute mark we discuss the snap to level movement in more depth.
There is also a chapter support section below Day 1 and my thought is to begin here to go a little deeper into that movement. You will find a Chapter 1 Assessment video here that goes in more depth about the surf to level movement at roughly the 2:45 minute mark. You will also find the Greatest Player and Athlete Body Movements Study, in this video at the (10:25) mark we start discussing the surfing movement using the greatest players.
Thanks for the question and the care and energy you are putting into the program.