Now that you have identified the tasks that will comprise your schedule,
the last step is to create the Relationships that will show the Dependencies
between the various Tasks in your Project. To create a relationship, you need
to identify two Tasks between which a dependency exists, and then what Type of
Relationship is necessary.
The most common Relationship type is Finish-to-Start, which means one
activity is dependent on the completion of another activity before it may
begin. As an example, you have to finish putting your pants on before you can
put on your shoes. You would describe this as a Finish-to-Start relationship
between putting on pants, and putting on shoes.
This basic relationship type is very straightforward, and can be used to
describe nearly dependencies you will encounter in planning a project. While
there are a few special cases where you may want to use other relationship
types, until you are more familiar with project scheduling, you can use
Finish-to-Start relationships exclusively in developing your schedules.
The above example schedule is composed entirely of Finish-to-Start
relationships.
Typically, a schedule will have a single start, and a single finish.
However, sometimes one or more Tasks will have no predecessors Tasks, and are
instead driven by external factors that require them to begin or end on a
specific date. In order to place such Tasks in their proper place in the
schedule, a constraint can be used. A constraint is an artificial restriction
on an activity that affects its start or finish, outside the logic of the
schedule (typical task/relationship logic).