I NEED TO LOSE WEIGHT!?

So, my height is 1.65cm and i weigh 62 kilos, people think i am fine but i really wanna go down to 50 kilos and tighten up my skin a little. My legs are pretty fat and i don't know how to get rid of it! i also want to tighten up my butt a bit. If someone could tell me what to eat and what to not eat or put me on a diet program to lose this weight, that would be great thanks!