Music theory for the guitar made simple. It all starts with the major scale. If you want to get a basic understanding of music theory and guitar theory, then start with the source. The major scale is what all other scales and chords get referred to or compared to. If you go to a piano and start with the c note and play all of the white keys all the way up to the next c note you have played a c major scale. There are seven separate notes in the scale, eight if you count the fact that you start and end on the same note. The thing that can make scales complicated, is if you try and memorize each note in each scale. It would be a big undertaking to remember each note in the (a) major scale and the (a flat) major scale and the (d) major scale and (c sharp) major scale. Instead I will simplify it to get you started, later if you want to be a more well rounded musician you can memorize all the notes. Instead memorize the pattern. When playing notes you have a whole step or a half step. This is why pianos have black keys. The black keys are half steps between each note. If you play a g and go a half step up to the black key you are now playing a g sharp, (or a flat). If you play the g then go a half step down to the next black key you are playing a g flat (or f sharp). Remember in music notes only go from a to g. If you look on the piano you will not see a black key between the (e) and the (f) notes. To go from e to f is only a half step. The same is true with the step from b to c. On the guitar each fret is only a half step. So if you play the top (a) note and slide your finger one fret to the right, (considering your playing a right handed guitar) your now playing an (a) sharp. You would need to slide two frets over to play the (b). So again to make it simple or get down to the basic part of the scale lets look at the pattern. The pattern for any major scale is this, whole step, whole step, half, whole, whole, whole, half. It does not matter which note you start on, If you follow this pattern you are playing a major scale. The first note you start on is the root note or the name of the scale.
Start this pattern on a d note and you are playing a d major scale. Start the pattern on an f# and you are playing an f# major scale. Look at the scales on this web site and look at the pattern for the major scale then apply it to the neck of your guitar. To play a minor scale you will play a pattern close to that of the major scale but with two changes. The third note and the seventh note will be flatten. So your pattern will be this whole, half, whole, whole, whole, half, whole. The first note you play is the root note, so if it is a b, you are playing a b minor and so on.
Now lets turn the scale into a chord. A chord is a group of notes you get from the scale that you can play at the same time or two at the same time or go up and down the chord in an arpeggio. So take a g major scale and take the first, third, and fifth note out of it and you have a g major chord. You will be playing the g, b, d, notes. You may notice that when playing this chord on the guitar you are playing six strings, but the chord only has three notes. The other strings are playing the same notes as well but at different octaves. The first note in the chord is also called the root note.
If we take the g minor scale and turn it into a g minor chord, we still take the first, third, and fifth notes out of it. If you look at the scales or look at the pattern you'll remember the third note gets flatten a half step. This is what makes the minor chord sound different. We are now playing g, b flat, d. Now here is where we tie it all together. You don't have to play a scale from start to end or up and down. Once you have memorized the pattern, play the notes in different order within the pattern and at different lengths. Now you are making up your own melodies. Play along with others and have them strum a g chord while you play a melody you have made up using the g scale pattern. If they play a d minor chord, you can play a melody in the d minor scale pattern. Please post questions or comments. It is my hope to make this more simple for the beginner. I tried learning the hard way and gave up many times as a result.