Im a a skinny ectomorph and decided I wanted to bulk up and i've managed to put on 11kgs (24lbs) in about 4 months. I feel more confident and have gotton lots of comments from family, friends etc about how much better I look. The best advice is to join a gym. Get a PT session or 2 when you join so that you can be shown a routine to stick with. Diet is also very important and you should eat lots of protein (shakes, chicken breast, tuna, salmon, cottage cheese, etc), complex carbs (wholemeal rice, wholemeal pasta, wholemeal pita bread) and a small amount of natural fats (avocado, peanut butter).
good luck dude.
ps - Make sure you dealift and squat!