Start out by practicing in the beginner mode and flying at low level 20 ft to 40 ftor so, any learning the controls and how they react in FPV. Until you are very familiar with all the controls and buttons on the controller. don't venture out very far. Start flying with the app while close in until you gain the confidence
While you are doing this watch the drone and then watch the screen so you can see has the controls react on the bird. When you are comfortable at close range, FPV, venture out 500 meters or so using FPV and then try to fly back--Pretty soon your confidence will increase with FPV-- it is actually easier, because the Phantom is flying exactly like you see it on the screen. You are sitting on top with a great birds eye view.