Rough order, not a ladder. Each track moves at its own pace: your chords can be here while your lead playing is still a stage behind. Nothing has to be mastered before you move on.
One shape, every key.
A barre chord is an open E or A shape moved up with your first finger as the nut. With those two shapes and the note names on the E and A strings you can play any major or minor chord.
Ready to move on when
You can play F and Bm as barres, and find any major or minor barre chord from its root on the E or A string.
Solo from the nut to the 15th fret.
The five pentatonic boxes tile the neck. Join them and you can solo from the nut to the 15th fret in any key.
Ready to move on when
You can slide from one pentatonic box into the next without stopping, in A and in one other key.
Hear where a song is going.
The circle shows which keys are neighbours (one sharp or flat apart) and which minor key shares each major's notes. Songs that change key usually move to a neighbour.
Ready to move on when
You can find a key's relative minor and its two neighbours on the circle, and name most intervals by ear.
E major
Key signature 4 sharps: F♯ C♯ G♯ D♯
How to read it
Clockwise each key is a fifth higher and adds one sharp (or drops a flat). Anticlockwise is a fourth higher and adds a flat.
Rings. Each major shares its notes with the minor inside it (its relative minor) and the diminished chord on its 7th.
The chords of a key are the lit slice: three majors side by side (IV I V), the three minors under them (ii vi iii) and one diminished (vii°).
Neighbours differ by one note, so modulating one step round sounds smooth. Moving anticlockwise is resolving: V to I, and ii V I walks two steps home.
Secondary dominants. The major one step clockwise of any chord is its dominant (V of V: D to G in C major).