Phone down by your side, top pointing at the floor. When it beeps, draw and point it at your opponent.
Both players type the same code on their own phone. The beep goes off on both phones at the same moment.
Hang it by your side, top pointing down. Keep still.
Wait for the beep. Keep it by your side, don't look at it.
Show your screen to your opponent. Next round starts by itself.
You drew before the beep. That's a foul.