Guitar Intonation

This video goes into depth on what intonation is and how to set in on your guitar. Below are the time stamps of the different sections. I suggest that you don't skip "Before You Intonate". Also below is the link to my video on setting the action at the nut.
5:28 Octave Explained
8:04 Range of the Guitar
11:32 Before You Intonate
13:00 Setting Intonation, The Process

String action at the nut: https://youtu.be/_RRv4PPN-Wc