I use this book in my Music Therapy sessions with Geriatric clients--and they love it! The songs are well-known and fun--mostly folk tunes like I've Been Working on the Railroad and My Bonnie Lies Over the Ocean. Chords are SO simple--no bar chords (so you may need a capo to adjust the key). If you're looking for the most basic way to play favorite songs...this is the way to go!
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.