To play an ascending version of a given scale, play each note displayed from that root (highlighted in yellow) to its octave (also highlighted in yellow) in ascending order (ABCD...etc). To play a descending version of the scale, start at the higher octave and play each note displayed in descending order (GFEDC...etc) down to the root.
In addition to showing the notes within one octave of the scale, all notes in that key are displayed for reference.