In the Gantt Chart, you can create a task dependency relationshipA relationship between two tasks. If a task is completed early or late, this has an effect on the start and end date of the task that succeeds it. between project tasks.
If you want a project task to be dependent on another project task, you can add a link between the task bars in the Gantt Chart. For example, you might want a task to start only when another task has finished.
You can add dependencies between tasks, or between parent tasks and another parent's children. You cannot add dependencies between a parent task and its own children.
To add a dependency:

To edit the dependency type or lagThis term is either a delay or an overlap between tasks in a dependency relationship. According to the dependency type, lag is added (or subtracted when a negative value) to the start or end time of the successor task.:
To delete a dependency:
Related Concepts
Project Planning Methodologies
Managing Project Tasks in Gantt (Beta)
Reference