You are asking great questions!

There are 2 ways of looking at modes & it's important to know which one you mean.

1. Structural: each mode relates to a parent scale. So you are always in one major scale, G major for example, and the various modes are just ways of playing a G major scale, but starting on each note in turn. Often this is used to stay in one key, but play over the chord changes within the key.

2. Ornamental: You just play whichever mode you like the sound of at the time regardless of the key. This requires that you know & apply the scale or mode interval formula.

I have 2 tutorials on modes that cover both of these approaches in detail.

https://www.guitartricks.com/tutorial.php?input=370

https://www.guitartricks.com/tutorial.php?input=770

Answering specific questions.

Originally Posted by: ethanquar

He goes over the minor scale and the 7 positions found on the fretboard. Are all of those aeolian? Or are they all of different modes?[/quote]

I'd have to see it to know for sure, but yes, what you are describing is possibly the diatonic modes. You use or stay in only one scale (major or minor). Since there are 7 notes there are 7 possible notes on which to start playing the scale. If you give each note of the scale a chance to start the sequence, then you are playing the modes of that scale.

That sounds more complicated than it really is once you start playing it. This is the structural point from above.

Originally Posted by: ethanquarThough they all have the same notes, the note they start with varies, so does this imply different modes?[/quote]

Exactly.

Originally Posted by: ethanquarIf so which position would I know to use depending on the chord changes?[/quote]

Using the modes to target chord changes is one way to use them. But in some cases this is just reverse engineering. It's usually better to start by learning to:

1. Play in key (find the scale).

2. Rhythmically target chord tones.

3. Build melodic phrases.

So, you could play ionian when the I chord happens, then dorian when the ii chord happens, phrygian when the iii chord happens, etc. But this is more complicated than it needs to be for most songs & certainly for beginner approaches to improv.

Originally Posted by: ethanquarWould it be wrong to play dorian over the ii chord?[/quote]

No, that's essentially correct. But as a beginner it helps to think of the major scale you are using that is the key signature. Then use that one scale to target the chord tones of the ii chord.

Example, you are in the key of C major. The progression is: C (I) - Dm (ii) - G (V).

When the Dmin chord happens just make a melodic phrase that uses notes of the C major scale, but that rhythmically emphasizes the notes d-f-a (the chord tones of the Dmin chord). That's much more conceptually clear & more efficient than trying to think of an entirely different mode for every chord change.

This is the distilled essence of my improv tutorials.

https://www.guitartricks.com/collection/learning-to-improvise

[quote=ethanquar]If I played an A minor scale over an A minor progession it would work anywhere, regardless of what the chord is right?

Yes, mostly. And that's a great beginner way of looking at it. But the next step to make your playing sound musically integrated is to target chord tones.

The note F is in the A minor scale. So it won't sound terrible to play the note F while the A minor chord is happening. But if you linger on, or rhythmically emphasize it, then it will clash with the note E which is in the A minor chord.

However the F note is in the D minor chord. So lingering on or stressing the F when a D minor (iv) happens will make your playing sound more melodic & integrated with the chords as they change.

[quote=ethanquar]Also, what makes a mode a mode is the spacing between each note and the texture the intervals provide right?

Yes, great observation. The unique characteristic of any scale or modes is the interval formula (the distances between all the notes). I would say the unique sound, where you said "texture".

[quote=ethanquar]What mode you are playing is most obvious when you play the scale in order; but when we solo, we don't play the notes of the scale in order, we hand select them as we are playing to formulate the desired tone; so, what would be the point of soloing with mixolydian when I could just use ionion (both of which have the same notes).

Great question. This is what I meant by reverse engineering. Sometimes it's best to use a mode identifier like mixolydian after the fact to identify what someone did. Or to describe a certain part of a solo: "Sounds like he was using mixolydian for that solo or phrase".

Rather than use it as a system to start, "Now, I'm going to play mixolydian". Because often then a beginner will wind up sounding like a robot automatically running through an alphabet of notes rather than trying to play music. Make sense?

Having said that, there is the ornamental approach (point 2 from above). Some songs, and more advanced improv methods, do actually just use a mode without any reference to key or scale. At a certain point all the musicians will know ahead of time, "Now we are using mixloydian".

This approach is especially used in jazz. For a whole song, or a section of the piece everything switches to some non-key signature related mode simply to get that unique sound at that point in the piece.

[quote=ethanquar]If I were playing them in order up and down it would make sense because you can hear a significant difference between the emotive language, but when improvising we don't play up and down.

Right. Which is why it's good to think in terms of key, chords & melodies at first.

Hope this helps! Please ask more if necessary!