Not sure if this is what he has in mind. Offered for what it is worth. See that diminished chord and your digital pattern will be:
R-b3-b5-b7
Code:
Major Scale Box.
G|---2---|-------|---3---|---4---| 1st string
D|---6---|-------|---7---|---8---|
A|---3---|---4---|-------|---5---|
E|-------|---R---|-------|---2---|4th string
Basic Chords
Major Triad = R-3-5
Minor Triad = R-b3-5
Diminished Chord = R-b3-b5
7th Chords
Maj7 = R-3-5-7
Minor 7 = R-b3-5-b7
Dominant 7 = R-3-5-b7
½ diminished = R-b3-b5-b7
Full diminished = R-b3-b5-bb7
Scales
Major Scale = R-2-3-4-5-6-7
Major Pentatonic = R-2-3-5-6
Natural Minor Scale = R-2-b3-4-5-b6-b7
Minor Pentatonic = R-b3-4-5-b7
Blues = R-b3-4-b5-5-b7
Harmonic Minor Scale = R-2-b3-4-5-b6-7
Melodic Minor Scale = R-2-b3-4-5-6-7
Major modes
Ionian same as the Major Scale.
Lydian use the major scale and sharp the 4 - yes, it’s that simple.
Mixolydian use the major scale and flat the 7.
Minor Modes
Aeolian same as the Natural Minor scale.
Dorian use the Natural Minor scale and sharp the b6 back to a natural 6.
Phrygian use the Natural Minor scale and flat the 2.
Locrian use the Natural Minor scale and flat the 2 and the 5.
Generic Notes.
The root, five and eight are generic and fit most any chord. Remember the diminished has a flatted 5.
The 3 is generic to all major chords. See a major chord R-3-5-8 is a generic bass line that will work.
The b3 is generic to all minor chords. See a minor chord R-b3-5-8 is a generic bass line that will work.
The 7 is generic to all maj7 chords. R-3-5-7.
The b7 is generic to all dominant seventh and minor seventh chords. R-3-5-b7 or R-b3-5-b7.
The 6 is neutral and adds color, help yourself to 6’s. I like R-3-5-6 for major chords. Has a great sound.
The 2 and 4 make good passing notes. Don’t linger on them or stop on them, keep them passing.
In making your bass line help yourself to those notes, just use them correctly.
Remember roots, fives, eights and the correct 3 will play a lot of bass.