After the necessary certificates have been requested and assigned, the Lync Server 2013 Mediation Server services can be started:
1. Beneath Step 4: Start Services, click the Run button.
2. Click Next to begin starting all the Lync Server services.
3. Click Finish to complete the wizard.
The wizard does not actually wait for the services to complete startup. Use the Services MMC to view the actual service state.
At this point the Mediation Server installation is complete and it should be functional.