I just had an American Standard whirlpool installed during my bathroom renovation. The plumbing crew filled it up with a foot of water but didn't drain it. Now I tried to drain it by following the instructions that came with the tub but that didn't work! The instructions say pushing down on the pop-up drain cap at the bottom of the tub to drain. Nothing happened. What did I do wrong? I checked: all the plumbing pipes are in place and connected. Thanks in advance for any suggestions.

If you unscrew the pop up piece one or two turns it should give enough clearance to drain the tub.
If the problem is further down in the plumbing you may have to take the pop up all the way out and check for a blockage downstream.
Either a plunger or a sewer snake.