It's not about intervals, but the notes from a triad. He makes a sequence with the notes from a particular triad, C in the examples.
The brackets in the examples show the sequences.
Let's number the notes in the triad
C = 1
E = 2
G = 3
C = 4
Ex1
G C - E G - C E
here it's a 2-note sequence. You take one note of the triad en play the next note of the triad after that. Then you start on a different note of the triad followed by the next note, etc
3 4 - 2 3 - 1 2
G, 1 step up => C
E, 1 step up => G
C, 1 step up => E
Ex2
A 4-note pattern
G E C G - E C G E
3 2 4 3 - 2 1 3 2
G, 1step down => E, 2 steps up => C, 1 step down => G
E, 1step down => C, 2 steps up => G, 1 step down => E
Ex3
Again a 4-note pattern
E C G E - C G E C
2 4 3 2 - 1 3 2 1
E, 2 steps up => C, 1 step down => G, 1 step down => E
C, 2 steps up => G, 1 step down => E, 1 step down => C
Hope this helps