What is Osa Sync supposed to do: Basically this is simple: keeping the contents of Outlook folders the same on multiple computers (=synchronization).
How does this work: Osa Sync keeps track of all changes made in a synced folder and copies these changes to temporary data files.
Osa Sync permanently monitors your synchronized folders for changes and creates update files if there are.
So your folders will stay in sync automatically; you do not have to run a synchronization process manually (except a one time only synchronization preparation process). Nothing happens until you tell Osa Sync explicitly to keep a folder synchronized by running the prepare folder for synchronization wizard and choosing the folder you want to sync.
If you create a new contact in OE it is also created (by Windows) in the Outlook contacts folder.