When you press the "Stop" button on the iPad, we land the drone. This is for safety reasons. However you can build your own remote, but programming buttons on the iPad to "turn 15 degrees to the right" and use those buttons as the drone is flying. There are two ways to send commands from the button to the drone Actor.
You can use messaging commands such as "send message" and "when I receive". So when you tap on the button, send a message to the drone actor. In the drone Actor, use the receive event and program a course of action.
You can also define a function in the drone actor, and call it from the button Actor as drone.turnleft(15).