I am a little bit thin. i am 16, height 175cm. but my weight is only 48 kg. please give me some advise to increase my weight as the normal teens, thx?

Increase calories &: muscle training. It takes about 3500 cal to gain 1/2 Kg or 500/d. This can be accomplished by increasing portion size, adding some calorie dense foods like nuts, oils or shakes to a healthy diet, or adding snacks to your daily routine. Do some moderate muscle training, so the weight gain will go on as muscle instead of body fat. Calcium is important for bone growth, so get at least 4 daily/d.