Dependencies
Add A Dependency/Link Between Tasks
To have a task’s start date determined by the completion date of a previous task, you make the task “dependent” on the prior task. Dependencies can only be added after a task has been created. The dependencies column is has the 
symbol in the header row.
To create a dependency for a task (link its start date to the end date of a previous task), click the box in the dependencies column to the right of the task. The dependencies window will open.
You will be presented with a list of the tasks within the current project (tasks can only be dependent on other tasks in the same project). Browse through the task levels by clicking on the arrow to the left of summary tasks (if any). Select the task on which the current task should be dependent. The linkage between the two tasks will be added, and you will be returned to the Task List. You can also add a sequence of dependencies to a set of tasks by clicking the left selection checkbox on several tasks and then clicking the Link Tasks button.
Delete A Dependency
To delete an existing task dependency, from the Task List or Gantt chart, click on the dependency icon on the task row (located to the right of the Duration column). On the next window, under This task is dependent upon: click the x link next to the task you wish to unlink.
Highlight When Predecessor Is Late
The dependency symbol for a task will show an pink background if a task on which it is dependent is late. This applies only to tasks that are directly dependent on the late task (not all subsequent downstream tasks).
The responsible party for a downstream task can be sent an automatic email notification once a task upon which the downstream task is dependent is marked as complete. This is set for a particular workspace under Settings on the Auto-notifications page.