You must use your plan throughout the project to make sure
you are on schedule. Save your initial plan and then save a second version,
which will be the one that you amend as you go along.
Some things will take a longer or shorter time than you
expect and that is perfectly OK.Record the changes to the plan and the reasons why you had to make
the changes. If you have forgotten to include some tasks, insert them and
include a comment.
Remember to leave time at the end in case you get behind
schedule for any reason.