Critical Path Method (CPM)
This tool, also part of the software suite, is an excellent method that helps the Project Manager to understand how the tasks are related to each other. It also describes the Critical Paht, which is the list of tasks that cannot be delayed without delaying the whole project.
Each task needs to be defined with the Earlier Start and Earlier Finish, as well with the Late Finish and the Late Start. The slack is calculated when the tool check the dependencias, so that Tasks that are not part of the Critical Path will have a Slack different than 0.