1. need everyone available to help with something
we are going to need all hands on deck to complete the order in time
If a lot of work needs to be done, you will need 'all hands on deck' to get it done. This means that everyone who is available to work is needed. If 'all hands are on deck', this means that everyone is working hard together, and that no one is left idle. This is usually used in case of an emergency or when there are time constraints for the completion of a task or project.