To take a selfie from a hundred meters away he’ll make his own camera using a Raspberry Pi, the camera module, some additional electronics, and a laptop that will be the ground station to control the whole contraption. B4-4 rockets will be used to push the contraption. B4-4 means class B rocket with 4 seconds of thrust and 4 seconds delay until the secondary charge fires. To push the rocket 100 meters in the air he’ll need to calculate the force needed to be exerted by the rocket motor in relation to the weight of his final rocket. You can simulate the flight with dedicated software like “openrocket” on Linux. Clem 3D prints a rocket design from Thingiverse using PLA.