If you're skinny or very lean you will have to gain weight to add any muscle to speak of. The faster you gain weight the faster you will add muscle - to a point. As pointed out in that article it is important not to confuse training methods with 'training'. First - take a good look at yourself and be honest about your needs. If your arms, chest, legs or whatever are already big then concentrate more on the other areas of the body - work to balance things out.
Some people have good results with training a different bodypart each day, once a week.
If you're training for size I lean towards a 3 day on and 1 off routine. Young people can generally handle more training time, however this is not always the case. Effort - the most important factor. Keep your workouts short and intense. The best training method has been developed from years and years of research - by top Universities, from top research faculties and from the elite sport organizations, as well as other sources.