You might think that, you'd be wrong. I know what a relative minor is, I play guitar daily. I can play up and down the circle of fifths/fourths and improvise endlessly over the harmonized major/minor scale playing right through the changes. None of that knowledge helps decipher the purpose or meaning of the instructions you gave.
I'll try and walk through it.
> If "major" then switch to the relative minor, or vice versa.
OK, home chord is Em, so we'll use G major.
> Go Round the circle of fifths or the circLe of fourths either direction, but stay on whichever side of "major/minor."
OK, that's C or D given G as the starting point.
> Go up or down the scale, staying on whichever side of "major/minor."
So playing the G, C, or D scale over an E minor progression. G makes sense, same scale as Em; C or D... don't even parse for me. I don't think of chords and scales as separate, changing the scale changes the underlying chords I'd play under them, thus changing the key to something other than Em.
> So for example, a tune set with E minor, G major, A major should work.
What? Nothing you just said would lead me to think A major would work over an Em progression. G major, sure, obvious, it's the relative major of Em and just another name for G major scale, but A... why A, you haven't explained that above, your example doesn't match what the instructions seem to say.
Then what you don't understand is how a trad tune set works. What I'm talking about is how to put together a set of three tunes that work well as one track on an album or one "number" in a performance. Each tune internally has its own progression, which may be different. I'm only talking about the home chord of each tune. (Which I state.)
True, but I wasn't. You really weren't as clear as you seem to think you were. If all you're saying is pick as roots nearby notes on the circle of fifths, you could have been much clearer.
I'll try and walk through it.
> If "major" then switch to the relative minor, or vice versa.
OK, home chord is Em, so we'll use G major.
> Go Round the circle of fifths or the circLe of fourths either direction, but stay on whichever side of "major/minor."
OK, that's C or D given G as the starting point.
> Go up or down the scale, staying on whichever side of "major/minor."
So playing the G, C, or D scale over an E minor progression. G makes sense, same scale as Em; C or D... don't even parse for me. I don't think of chords and scales as separate, changing the scale changes the underlying chords I'd play under them, thus changing the key to something other than Em.
> So for example, a tune set with E minor, G major, A major should work.
What? Nothing you just said would lead me to think A major would work over an Em progression. G major, sure, obvious, it's the relative major of Em and just another name for G major scale, but A... why A, you haven't explained that above, your example doesn't match what the instructions seem to say.