You can't target weight loss. That means you can't try to lose weight from one part of your body. You just gotta lose weight in general.
Losing weight is a matter of burning more calories than you eat. There are many ways to go about doing this. You just have to burn more than you eat. So you can eat less & exercise little or not at all. You can eat the same & exercise more. Or you could eat more & exercise a LOT.
Myfitnesspal is a great app for tracking what you eat. If you don't track what you eat you may find it difficult to lose weight since the natural tendency of the body is to eat more if you exercise more.
An easy way to be sure to not eat too many calories is to eat mostly vegetables. Drink only water & maybe unsweetened tea or coffee. Liquid calories are too easy to consume & cutting them out can make a big difference alone.
I eat carbs in very limited doses since they are often calorie dense without the nutrition i want/need. Most of my calories come from protein & fat, even though the great majority of what i eat is vegetables, they have barely any calories.
Any exercise is good. Walking, cardio like jumprope or aerobics. High intensity interval training is a good calorie burner. Weight lifting is super beneficial & more muscle mass means you burn more calories.
But a simple program of incorporating more veggies into your diet, cutting down on processed foods, sugars, and liquid calories, monitoring your food & developing some better habits, and starting something simple like taking a walk everyday, can really work wonders in the long run, since it's the things that we can stick to and build on that really work. Starting an intense training program & very strict perfect diet are habits most likely not going to last & many ppl just end up back where they started.