This scale pattern is also known as the 1231 2342 pattern, which refers to the scale degrees. If you were to name the notes it would be GABG ABCA and so on. Before applying this to your instrument, listen to the tab a few times to get the sound of the pattern in your head.
This is a 3rds pattern scale, which looks like this - 132435. The pattern is up a third, down a second, up a third, down a second. Make sure you check out the right hand fingering for this one, as it's a little funky.
Learning the modes is a great way to develop a comprehensive understanding of the banjo's fretboard. These modes are just the G major scale starting on notes other than C. For example, the second mode in this tab starts on the A note. For this A Dorian scale, you're playing all of the notes in the key of G, it's just starting on the A. Therefore, the notes for this scale are ABCDEF#GA.