how do you install a set of herf bars or steps on a 2006 liberty do you have to drill holes?

Many steps mount using existing holes under the vehicle. Some require drilling. It all depends on what type of step and what brand you get to determine how they will mount. Mounting steps on a unibody vehicle is a lot more complicated than on a pickup truck. I have been installing accessories for 19 years and in most cases this is not a job for the average do-it-yourselfer.