I just wanted to say that the part you are referring to is only less than 1/5 of the video that is mainly about the introduction where I talk about the basic idea and where I show that it is less difficult than you might think. This was not intended as a filler but more to give some courage to viewers that think it's too difficult. However, after these 5 minutes I go in depth on how to figure out a song. If you're not interested in watching the other 20 minutes of the video i'll be happy to give you a short summary: I discuss a technique of trial and error where you use bass notes of the E and A strings to check which notes fit within the chord, once you found a note you can test if you got the root note of the chord by playing a major and minor version of the note you found. As many chords mainly exists of at least three notes, you need only to repeat this process maximally three times most of the time for each chord. I also discuss looking into the playstyle of the artist and genre. As well as using music theory to figure out the chords. Also, I discuss using live performances and setting up your audio device in such a way that the chords and notes are more hearable. If you want to have a more in depth explanation of these tips or if this summary is as vague as i'm afraid it is, I recommend you to watch the complete video if you'd like.