After you select products and update classifications, you are ready to synchronize WSUS. The synchronization process involves downloading updates from Microsoft Update or another WSUS server. WSUS determines if any new updates have been made available since the last time you synchronized. If this is the first time you are synchronizing the WSUS server, all of the updates are made available for approval.
To synchronize the WSUS server
On the WSUS console toolbar, click Options, and then click Synchronization Options.
Under Tasks, click Synchronize now.
After the synchronization finishes, you can click Updates on the WSUS console toolbar to view the list of updates.