Hey man..
I myself am not strong in theory, but I would advise that you actually try out a scale. The article you gave has the Aeolian mode, which is also the minor scale. Go learn and play around with the scale over a progression, in which this case will be a Fmaj, Dm, Bb and C. You will notice that not only does it sound good, but also the notes will gel with the progression, hence a relative scale. I always think of it as matching DNAs.
I'll try to put this into application.
To make it easier to understand, We will be using Dmin as the first chord of the progression, followed by Bb, Fmaj and finally C. We'll be playing a chord on a bar each, a repetition of 4 counts over a 1/4 beat at a moderate pace. You can use an acoustic guitar as well to play it.
So while you are doing that, I will show you in tab form an example of a simple solo with the Aeolian and Ionian.
-------------------------------------
-------------------------------------
------------------5h
7~--------------
---------5----7----------------------
--
5-7-8----8-------------------------
-------------------------------------
Dm
-------------------------------------
-------------------------------------
--7-9-10-9p7------------------------
--------------10-7h
8~---------------
-------------------------------------
-------------------------------------
Bb
-------------------------------------
--------------------
6~--------------
---------------5h7------------------
-----6-----5h7----------------------
-6/
7---
7----------------------------
------------------------------------
Fmaj
-13-12-10-12-10-----10----------------------------------------------
------------------
13-----
13--10-11-10-----
13-11-10------------------
----------------------------------------12-----------12-10-9---------
----------------------------------------------------------------
10~--
----------------------------------------------------------------------
----------------------------------------------------------------------
Cmaj
So as you can see, there are lots of relative notes in a scale and knowing the notes is key to making a good tune. You can see that for every chord is being played I put it in bold to show that it has its place in the scale. Notice how they sound good together before you even reach the desired note? It shows that you must never forget the scale and progression you play in before you jam it out.
And before you know it, you'll keep it going with other scales besides the Ionian and Aeolian. You'll be able to understand and play it together with Phrygian, Mixolydian, and other modes, although I personally enjoy the sounds of Aeolian and Phrygian more.
Cheers and good luck!
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