Written above these two measures of tablature are chord diagrams. Every song has a
chord progression. Without getting too technical, individual notes (one tone) combined together in certain ways make up a "chord." Certain chords combined together make
up a "key." Most of the songs on this site are in the key of G. The most commonly used
chords in the key of G are G Major, C Major, and D Seventh, but these are usually just called G, C, and D (or D7).
Chord diagrams are basically just a picture of where the fingers of your left hand should
be holding down the frets. If you hold your banjo straight up facing you and look at the
first four frets, that is the picture that the chord diagram is showing. In more advanced
playing up the neck of the banjo the starting fret is denoted by a number on the left side of the diagram, but you don't need to worry about the for now.
The first diagram above shows the G chord. Pretty easy, huh? Since the banjo is tuned
in an open G already, playing all of the strings open gives you a G chord.
The second diagram shows a D7 chord. Notice how the tablature corresponds to the
chord. Try holding this chord with your left hand and playing the measure of tablature. Holding down the notes and getting a clear sound takes a lot of practice but is easy
once you get the hang of it.
The metal wires that separates the spaces on the banjo are called frets (1st fret, 2nd
fret, 3rd fret, etc.). The D7 chord should be played with your first finger just behind the
1st fret, 2nd string -- not on top of the wire fret and not in the middle of the space, but
just behind the fret (which makes it easier to hold down). Your middle finger should hold down the 2nd fret, 3rd string. The rest of the strings are played open.