Ok, I read the Scale Intervals doc and I wish to simply add on a little.
All of my examples are formulated from the major scale(Ionian) so when I b the III VI and VII steps of the Natural minor scale(Aeolian). I'm using the steps of Ionian to give the steps of Aeolian in which case they will need to be flatted.
In major or minor or whatever people choose to refer to them as now these are the scale formulae.
H- Half, W- Whole; Half is one fret, Whole is two frets up.
fe: fret 3 on the low E is a G, one H up and you hit G#/Ab, two H's(one W) up you hit A.
There should not be any errors as far as information goes and the conduction of that information should be equally as correct as far as my typing capabilities I suck.
I. Ionian(natural major)- I- II- III- IV- V- VI- VII- I
Steps- W- W- H- W- W- W- H
fe: Cmaj: C- D- E- F- G- A- B- C
Dmaj: D- E- F#- G- A- B- C#- D
Hopefully that gets the general concept of the first mode down.
II. Dorian(a form of minor, from major)- I- II-bIII- IV- V- VI-bVII-I
Dorian(from natural minor, easier)- I- II- III- IV- V- (natural)VI-VII-I
Steps- W- H- W- W- W- H- W
fe: D Dorian: D- E- F- G- A- B- C- D
A Dorian: A- B- C- D- E- F#- G- A
Now for the third mode.
III. Phrygian(form of minor, from maj)- I- bII- bIII- IV- V- bVI- bVII- I
Phrygian(from natural min)- I- bII- III- IV- V- VI- VII- I
Steps- H- W- W- W- H- W- W
fe: E Phrygian: E- F- G- A- B- C- D- E
A Phrygian: A- Bb- C- D- E- F- G- A
IV. Lydian(form of maj)- I- II- III-#IV- V- VI- VII- I
Steps- W- W- W- H- W- W- H
fe: F Lydian: F- G- A- B- C- D- E- F
C Lydian: C- D- E- F#-G- A- B- C
Now I see why people don't bother to try to explain this stuff in forums very much. If all of the viewers understand this I'm going to be off like a prom dress. But as long as I help just one person I will feel as though this post was worth my time.
V. Mixolydian(form of maj, actually dom)- I- II- III- IV- V- VI- bVII- I
Steps- W- W- H- W- W- H - W
fe: G Mixolydian: G- A- B- C- D- E- F- G
A Mixolydian: A- B- C#- D- E- F#- G- A
Now for the next.
VI. Aeolian(Natural minor)- I- II- bIII- IV- V- bVI-bVII- I
Steps- W- H- W- W- H - W - W
fe: A Aeolian: A- B- C- D- E- F- G- A
B Aeolian: B- C#- D- E- F#- G- A- B
Now for the least liked/used due to its diminished tonic.
VII. Locrian(diminished)- I- bII-bIII-IV-bV-bVI-bVII- I
Steps- H- W - W- H- W- W - W
fe: B Locrian: B- C- D- E- F- G- A- B
A Locrian: A- Bb- C- D- Eb- F- G- A
That's it for the modes of the natural major scale, it helps to learn these and then go towards chord formulae, that way you know that modes I, IV can make beautiful maj 7th chords, where as in the same key modes II, III, VI can make min 7th chords, the V of that scale can make a beautiful dom 7th chord, and your VII step makes up your min 7(b5) chord. I don't feel like doing anything more than skimming the top on that subject for now though, tell me what you think of this and if it helps, if it doesn't I will not bother going any deeper. This post is not too deep but as with all of music it does take time, patience and a lot of studying if you don't already know this, next up I will explain more about chords, exotics, pentatonic modes and so on and so forth. I've had multiple theory courses and of course I order many books and movies, if you wish to hear more from me let me know. So before I involuntarily stab myself in the eye for the redundant words. Later.