I need help on losing weight i find it really hard and dont no what to do please help!?

im 17 female and about 16 stone am trying really hard to lose weight but i dont no how i want to start running as i have a beach near my house but im worried incase people look at me! i have a fatty tummy bingo wings arms my legs are big and am normally around a size 18 in th uk i really want to get down to atleast a 12 or a 10, i really want to be able to go on holiday next year with my boyfriend and go in the pool or even on the beach! i dont no what foods i can or cnt eat i find it really hard i never no what work out to do if anyone could give me some tips i would be so happy!