Tomo Fujita Guitar Wisdom

Hey
At 14:04 on the video tomo plays the d harmonic minor scale from the root D note on the A string of which I understand but I don't understand the scale on the strings 123
Any help guys

Thanks 👍

Here is Tomo's comment:

"Thanks so much for subscribing to my Guitar Wisdom. You may want to write the notes out, by name and degree, and play them slowly. Try to play this scale (or any other scale) on ONLY ONE string, so that you can hear the intervals. Take your time!"