In Blues and Boogie piano playing, there are many different left hand patterns which can be used. Here are some common ones with a simple right hand part played over them. Learn each one from memory and then apply it to the 12 Bar Blues progression. When you are comfortable with each new left hand part, try it with some of the right hand parts from earlier lessons, and then try improvising over it. It is also important to repeat this process in many different keys. Playing in all keys is dealt with in lesson 35.
Most of these left hand patterns work equally well swung or played straight - experiment.
Here is a two bar pattern which works well both straight and swung. These are just a few of the left hand patterns used in Blues and Boogie piano playing. It is important to listen to albums featuring piano players and learn to copy what they are doing. You should also constantly experiment and make up your own parts. The more you do this, the easier it gets.