This is by far the best online instruction. The fact you receive instruction from an established professional musician who wants to hear and see you play and has the enthusiasm to want you to become the best guitar player/musician you can be speaks volumes about the level and dedication he has towards his students. This is a great value and I recommend it to everyone I know who is learning guitar.
Unlike many string instruments which use a bow to create a sound, guitars are played by plucking or strumming the strings on the instrument, which vibrate to create a sound. Chords are played when the guitarist holds their fingers down on more than one individual string to change its length, which in turn changes the frequency of the vibration created - in other words, it creates a different note. Performers often use guitar tabs, rather than sheet music, when learning music: this acts as a kind of 'map' to teach guitarists where to put their fingers on the strings.