You are looking for terms related to der Abmarsch.
Los, Abmarsch!
It's the departure of a larger group from one location. As soon they begin to move, it's hard to have them come to a halt again so you better be suited and booted before you do it. This is checked with the adjective abmarschbereit:
Macht euch abmarschbereit!
Alles abmarschbereit?
Wir sind abmarschbereit.
It sounds a bit militaristic, by purpose. It's the only way to tame a swarm of children.