*get on* (something) [Opposite: get off something]
Definition: to sit on a bicycle, motorbike or horse etc.
(This phrasal verb has more than one meaning)
E.g.1. The bike was too big for him. When he got on it, his feet didn’t touch the ground.
E.g.2. He got on his bike and rode as quickly as he could.
This phrasal verb can’t be separated.