To board or climb onto a vehicle, such as a bus, train, or plane. She managed to get on the bus just before it left the station.
To make progress or advance in a task or situation. He needs to get on with his homework if he wants to finish it before dinner.
To have a good relationship with someone. I really get on with my new colleagues at work.
To continue doing something, especially after an interruption. After the meeting, we got on with our work.