Write it in simulation. Run it on the floor.
The live arena is designed to accept the same program a team wrote for the simulated tank competition. The tank sees its position, heading, energy and what's in front of it, and sends back the same kinds of commands: turn, move, aim, fire. Teams can build and test in the simulator for as long as they like, then load their code onto a real tank and find out what the sim didn't tell them.
That gap is the lesson. Motors don't turn the exact number of degrees you asked for, sensors are noisy, and batteries fade by the fourth round. Teams that planned for all of that in their pitch tend to win on the floor.