They advertise usually once every year or two on the local news about their need to hire a couple hundred drivers. Their ads are on just about every job website, some print ads, etc.
Upon applying you're basically contacted the next day, asked about your driving history, criminal background, any special certifications you have including if you can drive a manual transmission (you don't need to know how to drive a manual). Just about everything they ask you is outlined in the job description. In all you're simply called up, told to show up at whichever facility you applied for to do an orientation, go through paperwork and a written drivers test, given a quick 10 minute tour of the facility, and go do your drug test. Upon passing everything, you're then told to come in the next day, take a road test to make sure you can actually drive decent, then you're set free into general population.
The staff is generally laid back, but can be somewhat cut and dry about questions and answers. Unless something overly catastrophic happens, if you bring something to their attention, they just ask if you wrote it down on your evaluation.