Probably an airside driving permit training course, unless you will be driving specialist equipment, in which case you will get training and signed off to operate specific items of kit.
The ADP course is about half a day, depends on which airport you are working at. It familiarises you with the airport and stand layout, road signs, rights of way etc, and you normally have to complete an easy 50 question, multiple choice exam. You will normally have to renew this permit every 3 years.