This is just a start for pianists. The bass lines created by professional bassists will be more sophisticated that what I've given you here. But this is a start.
These techniques will create a simple left hand walking bass line in Blues. The principals can be used in Jazz standards.
To discover how these lines were created, do the following.
If I can help you further, please call me.
You've got to learn your instrument. Then, you practice, practice, practice. And then, when you finally get up there on the bandstand, forget all that and just wail.
I'm a professional pianist and music educator in West Toronto Ontario. I'm also a devoted student and teacher of the drums.