If you’re just looking to learn rhythm guitar – it shouldn’t take long. Avenged Sevenfold does a lot of Drop D tuning (it sounds fancy… but really it will make it easier to play). Look up the tab/chords for “This Means War”. You can play most of the rhythm guitar (if not all of it) with ONE FINGER. Learn the chords in Drop D and then learn the song. Once you have that down, move on to “Bat Country”. Same principle applies to “Bat Country”… learn the chords in Drop D and then learn the rhythm part of the song. The chord changes are faster, but the theory remains the same. N

YouTube videos are fine for learning a song, riff, lead, etc. But first you need to learn to play guitar, and yes, there is a difference between learning to play guitar and learning to play a song. So I would stay away from the YouTube thing for right now. The best option is always to have a teacher, and here is why. Any book or website can show you where to put your fingers to make any chord, that’s the easy part. What they cannot do is look at your fingers and tell you why your chords sound like crap. Or help you with why your chord transitions are not smooth and quick enough. There are mechanics that need to be worked on in the beginning, but only a person looking at your form can correct these. This is why so many self-taught players, no matter how good they become, usually have some very bad habits.
Another thing to consider is starting out on acoustic. I know that nobody who wants to play electric has enjoyed playing acoustic, but you will be much better at playing cleanly over time, and have better technique because mistakes can be heard much easier on this instrument. If you go the teacher route I'm sure they will have a more informed opinion than mine.
These are essential elements that you’ll need to wrap your head around if you want to play on a consistent basis. However, I realize that when taken as one collective group, it can look as overwhelming as picking up your guitar without any prior knowledge, if not more so. Because of this, let’s not worry about this info for now. Bookmark the articles, and return to them later – they’re not going anywhere.
You do not need long fingernails to play guitar. In fact, it's best to keep your fingernails short! As for the callouses, these may be unavoidable. If you would like to avoid them as much as possible, ask your guitar instructor about lowering the action of your guitar (the action is the distance between your strings and your frets) so that the frets are easier to press down on.
G Major Pentatonic Lick: So you’ve learned a pentatonic scale and you’re ready to start playing your own solos. Unfortunately, it can be difficult at first to make the notes you are playing sound more like a proper lick and less like a scale. In this lesson, Jody Worrell will show you how to mix intervals, change note durations, and use a variety of techniques to create an interesting lick. We’ll pull notes just from the G Major Pentatonic scale and play them over a loop of a G Major chord groove.
The guitar is a remarkably hackable instrument for a million reasons that will be revealed to you as you spend more time with it. As you go along in your journey you’ll find a million shortcuts and fun ways to learn fast. I’ve rarely heard any of this stuff from guitar teaches, so beware, trust your instincts, and learn from people who can show you where you want to be.