What is the purpose of the Dirigo 120 glide track foot brace system? I haven’t found much information on it online.
I’m guessing this is your first kayak? Foot pegs in a kayak improve paddling efficiency by allowing you to push against them to transmit more power through your core to the paddle on each stroke. All touring and sea kayaks and most better “day touring” kayaks have them. Molded sit on tops tend to have several “steps” for different paddler’s leg length for the same reason. The setting should be so that the position places your knees slightly bent and rotated and raised so they tuck under the cockpit coaming. Bracing against the foot pegs also allows for better control of the kayak in turning and edging.
There is a good video in this link by a guy demonstrating paddling position for the feet and legs using an ergometer so you can see how it works: