If your only just starting riding a scoot IMO you'd be better off flat first. Because I know when I first started trying to do tricks off things, no matter how small, it's really awkward.
Yeah learn it flat, or maybe off a little bank. The trick to it is to hop as high as you can with your feet, so you'll get more time to whip it around. As you get better at it you can go lower and lower with your feet untill you barely need to hop
I learnt it Flat. Because as a noob I was scared of doing it with any sort of speed, and you need a bit of speed to do it off a curb. Just do it flat anyway. Its a whip.
for you it would be easier to learn flat. after you either get really close on flat or start landing them take whips to other places such as banks, small stair sets and curbs.