hi,
Welcome to Health Care Magic, thanks for posting your query. I understand your concern.
Considering your age and height , the ideal weight should be around 64-75 kgs, and you fall short by 3-4 kg's. Hence there is no reason for you to be worried about your weight. But if you want gain muscle mass and look fit there are a few things which you can inculcate.
1. Include in your diet a high-protein food like eggs, meat, nuts, legumes and dairy products.
2. try taking a protein shake ( 1 cup everyday)
3. If you cannot eat much protein food, then you can also take
protein supplements in the form of protein powders or capsules .
4. exercising is a very good way of building up body mass, try joining a gym/ or workout at home with adequate appropriate equipments.
5. avoid
stress and meditate everyday for least 15 minutes.
Follow the above regimen for about 1-2 months and let me know about the progress,
Do write back to me if you need further assistance.
Wish you good health, and good luck with the body building.
Take care.
Regards.