That's the first time I've seen an electronics instruction manual use the term "pound"!
The instructions are suggesting that once you have it face down on a soft cloth, you grasp the bottom of the base neck (the part of the base that leads into the monitor) with one hand, and then, following the direction arrow shown, whack the silver metal prongs that form the base of the stand. So, if the monitor was still in its normal position, on a desk, the whacking hand would be traveling vertically downwards towards the silver base. Hope that helps.
Naturally you'd want to whack/pound it gently at first, and increase the force gradually until it separates.