There a two different types of task dependencies that can be set up using the Gantt chart:
• A Finish/Start Dependency – where one or more tasks are dependent on another task being completed before they can commence.
• A Start/Start Dependency – where one or more tasks are dependent on another task being started before they can commence.
To set up a Finish/Start dependency, click and drag the circle icon from the end of one task's bar to the start of another. The same applies to Start/Start dependencies, in this case however select the circle icon at the beginning of a task's bar and drag and drop it on the circle icon at the beginning of another task's bar.
When two tasks are linked the dependency will be displayed as a gold line; if correct just release the mouse to set.
To delete a dependency just double click on its connecting line.