Make sure the EV is at 0 or maybe a little under, as Robinb states its controlled with the wheel on the right.
A couple of tools in the app can also help you, one is the overexposure warning which produces a zebra effect on any areas that are overexposed, they don't show up in the footage. The other one is the histogram, but to honest if your new to this I would probably give that a miss just now.