How to lose belly fat(stomach fat) quickly...???!!!!?

i am a 17 yr old boy and i weigh around 75 height is 5 ft 8 inch.
i want to get rid of my belly fat as quickly as friends suggest me to go to a gym bt since i am a student,i get don't get so much free time.
can you please suggest me a way to lose belly fat quickly by simple methods.???!!!