The best way to start to learn "The Blues" is to dive into the C Blues Scale! I've found that the best fingering to start off with is thumbs on white notes & 3rds on black notes. If you'd like to figure out the blues scale for other keys, here's the pattern:
1, flat 3, 4, sharp 4, 5, flat 7.
Clear as mud? If you're confused, you probably don't know what "scale degrees" are. No problem. That's just a fancy way of saying "the notes of the scale." In C major, the "scale degrees" are C(1), D(2), E(3), F(4), G(5), A(6), & B(7). In D major the scale degrees are D(1), E(2), F#(3), G(4), A(5), B(6), & C#(7). The "flat 3" of C major is E flat, since the 3 is E. The "flat 3" of D major is F natural, since the 3 is F#. Experiment with the "Blues Scale" and GOOD LUCK!