By having a less suspicious name

You can't outrun a bad diet. Try to make some small lifestyle changes. Smaller breakfasts of oatmeal or plain yoghurt and some fruit. Cut sugar out everywhere you can, no more energy drinks and snacks while studying. Try to cut back on carbs, and no going for second helpings. Look for healthier options at your school cafeteria instead of that slice of pizza.

Personally I've had a lot of success with intermittent fasting and a 30 minute walk every day.

Cico - calories in / calories out. You never have to exercise if your goal is to just lose weight.

You’ll need to track calories in some way, and figure out your TDEE (calculators online).

Basically it’s simple math. Your body needs xxx calories to stay alive. If you consume more calories than your body needs, you gain weight. If you consume less calories than your body needs, you lose weight.

Exercise will help with building muscle mass, which consumes more calories than fat, so your tdee will change as you progress in your weight loss or fitness journey.