Tablature is the written form of music for the banjo. While it looks much like conventional music, tablature provides banjo-specific information, such as what string you play and whether the string is open or fretted.
The five horizontal lines represent the five strings of your banjo, with the top line corresponding to the 1st string and the bottom representing the 5th string. The numbers indicate left-hand fretting positions, with 0 standing for an open string.