The easiest way: first of all, you need remote control equipment, that is, receiving and transmitting. Then there are batteries, motors, rotors and wires. Of course, some of them use steering gears. As for what is needed, it can be replaced. Then there is the skeleton of the plane or the whole plane. You can first make a paper plane out of paper, first try whether it can fly, then restore your plane in proportion with kt board or foam, and then put power and control on the plane to fly. Ask again if you have any questions