A chord is a group of notes that are played together. The first chord you will learn to play is the C major chord, usually called the C chord. Chords are used to play along with someone who is singing or playing the melody of a song. Chords are written on chord diagrams.
To play the C chord, place the third finger of your left hand just behind the third fret of the first string. The other three strings are played as open strings. Strum all four strings.