How to drive/pump for speed down the line?

I see a lot of good surfers really pushing hard/pumping down the line on waves to make sections.
Ive looked around and found some advice on youtube but it is vague and leaves me with more questions than answers.
How can i learn and perfect this technique on a shortboard?
Ive looked around and found some advice on youtube but it is vague and leaves me with more questions than answers.
How can i learn and perfect this technique on a shortboard?