To enable Microsoft Project to start each task at its proper time, you need to link the tasks to each other, based on their start and finish dependencies.
For example, a clockwork exhibit crew will hang the clocks only after painting the walls. The task of hanging clocks is linked to the task of painting walls, because the start date for hanging clocks can occur only after the finish date for painting walls.
Once these tasks are linked, Microsoft Project will always schedule the start date for hanging clocks relative to the finish date for painting walls, no matter when these tasks occur. Thus, they avoid being tied (perhaps unrealistically) to a specific date. For example, if the original finish date for painting the walls is February 3, then the start date for hanging the clocks is February 3 or later. If painting the walls gets delayed 5 days later than originally planned, then Microsoft Project automatically gives hanging the clocks a new start date of February 8 or later.
The power of linking tasks is twofold:
When necessary, you can exercise even finer control by specifying overlaps and time gaps between tasks. The amount of overlap between two tasks is called lead time. The time gap, or delay, between tasks is called lag time. With Microsoft Project, you can add lead or lag time between any two linked tasks.