by the way, you may want about 5 pairs of main rotors and maybe 2 more main gears.
Main gears tend to crack when you crash. I've gone through 2 main gears already and it's been only 2 months since I started this hobby.

You can use hexagon shape drivers (you can buy a set of all different size from a dollar shop) for the main gear and main rotor.
Main rotor you use 2nd smallest to unscrew completely, then exchange them.
Main gear, you use the smallest to unscrew completely,
then use small + driver to unscrew 3 screws of the servo arms that are connected to your CCPM. Then you use small - driver to unscrew the metal rod that is guided by 'swash plate' guide.