FULL ANSWER
The job of ground staff is vast and varied. Some ground staff work directly with the aircraft, cleaning it inside and out between flights. These people must make sure the ramps, runways and surrounding areas do not have any garbage or debris present that could cause damage to the plane. Ground staff also includes technicians and maintenance workers that are responsible for making sure the plane is in good working order before takeoff, as well as those tasked with cleaning the cabin between flights.
Ground staff also refers to people who work in the airport terminal itself. Some ground staff are responsible for inspecting, storing and transporting luggage, while others stock the aircraft with food and beverage items that are distributed during flight. Some ground staff members work directly with customers to answer questions and provide information regarding flight times, delays and any general queries the customer has before boarding. Ground staff work with the aircraft, crew and customers to ensure each flight is safe and enjoyable.