I suggest you:

The most effective way is-

Don't be afraid of being tired. Keep exercising every day. You can exercise yourself: running, skipping rope, long jump, badminton, and even sit-ups, push-ups, squats and jumps. It depends mainly on your wishes. Exercise arm strength, don't lift dumbbells excessively, sit-ups, push-ups, exercise leg leg press, and suddenly take off. Stick to 1-2 hours every day. However, if you are already very thin, you can eat more green food and less calorie \ meat food. Never use diet products!

Stick to your satisfaction and don't give up halfway.