How can a skinny guy get buff? what to eat and how to get that fit body, get the most of what your body can look?

Weight lifting: Weight lifting. If underweight consider consuming more calories. Protein bars and shakes or booster can be helpful.

Resistance training: The key isn't so much food choices as getting enough protein and eating little enough carbs and fats so that you're hungry much of the time, to get rid of your body fat. Aerobic exercise will help burn calories and reprogram your brain. Weights / machines to add bulk -- heaviest you can handle. This guy did it in 90 days, you can as well.