Don’t get to focused on just practicing on the sim. The real thing will be different especially if your heli is not setup perfectly. ALTITUDE is your friend. Most likely in your first "real life" roll you will be losing 50ft altitude.
Setup: the basics, just make sure that you have a "V" type throttle curve, mid stick 0 pitch and pos/neg max the same.
Just go for it, as long as you are high enough you won't hurt anything. Do NOT stop in the middle of the roll, no matter what happens...

Good luck