How to increase endurance and stamina through exercise and what type of nutrition would be most suitable and what type of food to avoid for a 18 year?

Long question. it's hard to give you a good answer in 400 characters - suggest you adopt a regular program of aerobic activity for minimum 20 minutes/day then gradually increase to 1 hr/day. Nutrition has a lot of lore- but abundant fresh fruits and vegetables, minimize sources of animal fat, and lots of fiber in your diet are all good ideas.