At the other day we learnt how to use: “Off we go!” Right before saying that, you may say: “All set!”

US  Informal   prepared; ready  (Webster’s New World College Dictionary, 4th Edition).

ARE YOU (ALL) SET?
It means – 01: Do you have everything you need? Are you ready?
               – 02: Have you finished eating, and are you ready for the bill?

Example: – Are you all set? Are you bringing everything you need to finish the project? / -Yes, we’re set! Let’s go!
Tradução: Tudo pronto? Tudo certo?

See more at:  https://clubedoingles.com/10-expressoes-em-ingles-muito-comuns-entre-os-nativos/ and https://www.collinsdictionary.com/dictionary/english/all-set