On your marks, get set, go! - Idioms by The Free Dictionary
on your marks, get set, go!
on your mark(s), get set, go
An instruction to begin something, typically some kind of competition. The phrase is commonly used at the beginning of a race to indicate when the competitors can start. Is everyone ready? OK then, on your mark, get set, go!
on your ˌmarks, get ˌset, ˈgo! used to tell runners in a race to get ready and then to start: He raised the starting gun.‘On your marks, get set, go!’ he shouted, and fired into the air.