A Workback Schedule is a useful method that reveals the milestones that a project will have to meet. It forces you to think about what a successful project will look like, and the steps you will have to take to get there.
Creating a Workback can protect both the designer and client from setting unreasonable expectations for a project. The designer is able to foresee and establish any required buffer or lead times and include them into the Workback Schedule. The Workback may also reveal additional task requirements a project must meet that hadn’t been considered previously.
You can Google search to find plenty of resources on how to create a Workback Schedule.