E|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|----0-------0-------0-------0-------0-------0-------0-------0-------0------|
A|---------------------------------------------------------------------------|
E|0-------0-------0-------0-------0-------0-------0-------0-------0-------0--|

Using the thumb of the right hand, pluck the open 6th (low D) and open 4th (higher d) strings on the beat 
(1 2 3 4)and the "and" of the beat (@ @ @ @). The 6th string should sound on the beat, and the 4th string 
should sound on the "and" creating an 8th note (1 @ 2 @ 3 @ 4) pattern that alternates between the two D 
notes. By mastering the ability to play this pattern with only the thumb, you enable yourself to play 
independent melody lines and chords with the pointer (1st), middle (2nd), and ring (3rd) fingers while 
acompanying said melodies/chord progessions with a bass line. Once you've mastered the alternating bass, move
on to using just the thumb to play other aimple bass patterns...

 1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2...
E|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|---------------------------------------------------------------------------|
A|---------------------------------------------------------------------------|
E|0------0-------0-------0-------0-------0-------0-------0-------0-------0---|

  1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2...
E|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|--------0-----------0-------0-----------0-----------0-------0-----------0--|
A|---------------------------------------------------------------------------|
E|0---0-------0---0-------0-------0---0-------0---0-------0-------0---0------|

  1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2...

E|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|----0-------0-------0-------0-------0-------0-------0-------0-------0------|
A|--------0---------------0---------------0---------------0---------------0--|
E|0---------------0---------------0---------------0---------------0----------|

  1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2...

E|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|---------------------------------------------------------------------------|
A|----0-------0-------0-------0-------0-------0-------0-------0-------0------|
E|0-------0-------0-------0-------0-------0-------0-------0-------0-------0--|

  
Once the ability to play different patterns using only the thumb has been developed,practice altering your 
bass lines by mixing patterns and adding different notes periodically...

  1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2...

E|---------------------------------------------------------------------------|
B|---------------------------------------------------------------------------|
G|---------------------------------------------------------------------------|
D|------------------------------------0-------0-------0-------0--------------|
A|----------------------------------------3p0-------------3b-----------------|
E|0-------0-------0-------0-------0---------------0---------------3b------0--|

Once playing bass notes with the right thumb has become natural and can be sustained while playing in time, 
progess to utilizing the 1st, 2nd, and 3rd fingers to play the 1st (high e), 2nd (b), and 3rd (g) strings. 
Start by using all 3 at the same time to play a D chord on beat 1.

   D major  &  minor

E|---2---|       --1--
B|---3---|       --3--
G|---2---|       --2--
D|---0---|       --0--
A|---0---|       --0--
E|---0---|       --0--


  1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2 e @ a 3 e @ a 4 e @ a 1 e @ a 2...

E|2-------------------------------2-------------------------------2----------|
B|3-------------------------------3-------------------------------3----------|
G|2-------------------------------2-------------------------------2----------|
D|----0-------0-------0-------0-------0-------0-------0-------0-------0------|
A|---------------------------------------------------------------------------|
E|0-------0-------0-------0-------0-------0-------0-------0-------0-------0--|