This is a very simple song. The top line represents the first string, which you will recall is the high E string. The spaces between the lines are not used. Each number on a line represents a fretted note on that string. The number zero is an open string, the number one is the first fret, and so on. Try playing the tune. Take as much time as needed and do not worry yet about the timing.
Of course, print-quality sheet is impossible to write with plain text. Even when images can be used, they are often inconvenient: they take up more space and not everybody can write them. For this reason, there is a very informal and loose standard of "Internet tablature", using only ASCII characters. For example, the above tune would be written:
