I am not sure I am following, you ask us how to calculate the stop loss and give us the stop loss level?
Do you want to calculate your position size (i.e. how many lots to trade)?
So you’re buying at 1.9000 & your SL would be at 1.8880 so as DayDreamer worked out for you, that’s 120-pips. And as Orpexo asked & I agree with his questioning, it would seem that it’s the position size that you are after.
What you need to is take the stop-loss in pips & go slap it in the BabyPips position size calculator, put in your figures & set your risk as 2% & it’ll give you your position size.
Try it, I’d assume that this is what you’re looking for.