It is generally your job to determine when you need to start meeting deadlines. PS8 planning software can tell you when to start when developing your plan. They simply need to define the project with tasks, durations and dependencies, then the software will schedule the task backwards in time from the set finish date and indicate the latest date the product can be started to meet the deadline. It is basically the method of scheduling production backwards from the finish date to the start date and calculating the time and materials required at each stage of the process