In order to properly access the Lync control panel after installing Lync Server you need to either enter the URL of the server with the path to the control panel or configure the access URL on your deployment.
The first approach simply involves typing: , also noteworthy is that if you add the site to your intranet list it´ll authenticate on your behalf and you won´t be needing to type your credentials every time.
The second approach requires a little bit more work. You need to open the topology builder and capture the URL you defined above as the Administrative URL on the properties for the Lync Server. The URL has to be a new DNS entry like You´ll have to rerun Step 2 and Step 3 of the deployment wizard to update those settings but now you won´t have to remember the URL defined above.