Okay...where do I start? I am teaching myself guitar notation and I am stuck on something. I take no guitar lessons and I never have. Now, on my guitar dvd that I bought a few months ago there is a song called "Etude." The dvd is now teaching me about moving thirds in that song. The song starts with open G and open B for the first chord. The next chord is A and C. The next chord is G and D. And the guy on the DVD says to play G with a B instead. And that is supposed to be a moving third. But how do I know when to play G with a B on any other song because there is no sign indicating that it is a moving third chord? Does that make sense? I just don't really understand WHAT a third is and WHY I had to change the G to a B. And that's where I am lost. So if anyone can explain those two things to me, I'd GREATLY appreciate it! :D

Thanks,
DeathEater7