Right. OK. So set a limit buy (not OCO) for 22BTC at $400. And a separate stop at $475 for 10.
Edit: but I don't think you'll have enough margin available to set a 22 BTC buy, even at 2.5x. Maybe enough for 20BTC after profit, but that'd be close to being maxed out on margin, which I wouldn't recommend. Maybe just do a 15 BTC buy.
$3000x2.5=$8000.
$8000+10*$55=$8555
$8555/$400=21.3875BTC. That's why you can't do a 22btc buy, plus there's fees and swap. Can't do 22btc buy starting with $3000.
I understand the 3000x 2.5 is the max I can margin, but what is the + 10*$55?
That is the profit on 10*($455-$400).
Recommendation: practice with a very small amount (0.01BTC) first, so you can get used to how the platform works.