When everything is prepared and in place, then you can say that you are 'all set/ready'. This can relate to a task or project, or something you have been planning to do for some time. If you have a journey planned, and all your bags are packed, you can say, "I'm all set to go". You can use any variation on this expression, using 'to go' or not. "I'm all set" or "I'm all ready", means the same as "I'm all set/ready to go".

1. I'm almost ready to leave. I just need to find my wallet and then I'm all set.
2. We need to leave the house in five minutes is everyone ready to go?

1. Don't worry, I managed to fix your computer, so it's all ready to go. All you have to do is switch on.
2. The team are all set and ready to go! Just give the order and we'll begin work immediately.