Give me tips to be not fat

i used to be really skinny and pretty but puberty hit and i turned into an absolute pig and weigh 50 or 51 kgs when im 5 foot 1, but anyways, i dont even hate my body, nits just how swollen and chubby my face is and how big my upper arms are, im currently cramming for exams and dont have time to excercise too much so i just walk after every meal. and two years back i got skinny by starving and i probably had an ed but i actually do not care, like i st@arve a bit, but not to the point of it being too unhealthy or passing out, so i tsrated doing that again and i believe i can get skinny again by eating less as i did beore and by exercising. so give me specific exercise videos from youtube to lessen face fat and upper arm fat and belly fat please and ty