Knowing how to read harmonica tablature, or tab, isn't difficult. Harmonica tablature shows you which hole number on the harmonica to go to and indicates if you need to exhale (arrow pointing up) or inhale (arrow pointing down). When hole numbers are stacked, you play several holes. Holes you block with your tongue are shown as black rectangles.

Check out this sample tab:

When you bend a note down, the arrow has one slash for each semitone you lower the pitch of the note. When you bend a note up (when you overblow or overdraw), the arrow has a circle through it. For example, check out this sample tab: