“Nothing will work unless you do.”
Who said it: Maya Angelou, author of “I Know Why the Caged Bird Sings”
“It will work” is a way of saying “It will happen” or “It is possible.”
For example, “Our plan will work once the CEO agrees” means that after the CEO agrees, the plan will happen.
This quote by Angelou means that you must do work for something to happen.