DirSync will be schedule to synchronize every third hour, but sometimes you would want to speed it up after a change.
Or you can learn to use Synchronization Service Manager based on Forefront Identiy Manager 2010, which also will be beneficial later on.
If you DirSync have performed a sync allready, which you often have seens it is the last step upon configuration, you can easily rerun the tasks that ran last time the schedule sync did:
Select the first task, right-click and choose Run. Just click OK on the next windows or change it to Full if you don’t want it to do a incremental sync.
Continue with all four tasks that runs every time, but wait for the first task to be Success or Completed before running the next.