Arpeggiated - meaning the chord is played as separate notes instead of sounding together
Diatonic - The major scale, in this case C major
Circle of 5ths - Playing chords up a 5th, down a 4th, until all the notes of the scale have been played

Please refer to my lesson Thirds: The Building Blocks of Triads which will prepare you for this exercise. This first example uses open strings and starts with the third finger. Recognize where the triads are and what pattern you are playing them. Each chord is played twice. The G chord in bar 7 has the 7th added to make it a dominant seventh to resolve back to the tonic (C) in the last measure.

As always, start slowly and use a metronome to build up speed. As a warmup exercise, also concentrate on making every note clean and solid, especially when swtiching strings.