Im currently at level 11 in the work out program. I am 18 170cm and 65kg. When should i do cardio to burn fat of my stomach.
You should do your Cardio on rest days.
Burning Fat is done through going calorie deficit.
I really don't think you need cardio other than for cardiovascular health. By your stats........your pretty skinny soooooo, you need to bulk up. Not dirty bulk as you might have heard but lean bulk. You'll lose fat slowly but it'll be worth it. Don't focus on losing fat that much, gain muscle. Eat a lot! But eat healthy of course. Your an ectomorph, you'll lose fat with time. Just focus on building muscle for now.
Well I'd say cardio will be needed for some people to lose fat, like for me I don't want to eat less of healthy food, I already eat no junk foods, so instead of eating less healthy food, I do cardio depending wise. But if you're an ectomorph you mainly have a little bit of fat covering your small muscles, that's the reality, so bulking - (c)lean bulk is the way to go to increase your muscle mass hence you will lower body fat % with time and your muscles will pop out more. Great answer by Daniel.