1996Z15

I just bought a Flex polisher and, as a newbie, I was wondering how long I should work the polish once it flashes? I the video that was posted it appears that you make a few passes after its flashed. When you're done is there a lot of polish residue remaining or is the car virtually dry? I am concerned that, even though I am using the "X" technique to apply the polish, I may be using too much or not working a large enough area. Of course my car is black so that makes it extra fun.............