Hello
RunRunFar,
I will try to keep it simple too, but I don't promise.
Your last question is:
So how would that be considered in the key of Cmajor then? Totally different sound.
You got the idea wrong. C major does not mean you need to start and end on Cmaj chord or note. Imagine how dumb will be the music then
. Try not to set too much boundaries on yourself.
What Cmajor means is that you need to use the notes that are in the C major scale. Now I'm not going to explain to you how to tell which notes are in there, cos you WILL get confused. Instead I'm going to give you a web site to tell you this
.
C Major Guitar Scales
See? there are the notes of C major. - C, D, E, F, G, A, B
If you need the notes of D major just pick D major on the menu:
D Major Guitar Scales
D E F# G A B C#
Sorry the site is about guitars, but thats what I'm used to. You can google for a piano based site.
NOW!
what you need to understand and always do, are two things:
1. Every note that is in your song needs to be in the scale you choose. If your scale is C major, every single note needs to be from those listed above.
2. Every note of a chord you play, needs to contain notes from chis scale. Now calculating notes of a chord can be VERY confusing for someone not deep into theory, so there is a tool in this site for this too.
Chord Progressions
See? You chose C major scale and it told you what major and minor chords there are in it.
So if you want to play E chord in C major song that's fine. but it needs to be an E MINOR! chord, because E major contains an Gb note as a third which is not part of the C major scale - C D E F G A B but that's too complicated for now, so just stick to what the sites tell you.
If you wish play Fmaj, Amin, Dmin chords
.
I'm tempted to explain about chord progressions in different keys, but that's a little deeper into theory.
If you want other chords than just major or minor, this part of the site will tell you most of them:
Scales to Chords guitar tool
Choose a scale and it will tell you the chords, then use the other part to see what notes are there in it.
Then use whatever chord you wish of that scale as long as it sounds good and combines well with the others.
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After that read about modes.
After you understand that, read about voicings and inversions. But that may happen after 2-3-4 months.
After that go read something about common chord progressions on the net, BUT don't take it as a rule. when you construct chords and which one of them is first second and third just experiment. Don't stick to the I IV V I "rule" which you'll eventually find and on most sites they will tell you that sounds best and most harmonic, because bla bla bla. Try to tell this to a jazz musician
.
For now stick to the first part of my post. The second is just a guideline on how you should further approach music theory. In time you'll begin to understand WHY something sounds good
.
Good luck man
.