To add to 2VoltFamily, these features may only be available in the premier but not sure. I have all these features on my 2016 premier volt.
The far left of the three buttons is the "automatic parking assist" (APA) feature which will help you parallel park or perpendicular park your car. The middle button is a "parking assist" feature which alerts you as you get close to objects in the front (FPA) and in the rear (RPA). All these are on/ff toggle switches.