I will do it by using Setup on my Domain Controller from Lync installation media as described here: http://technet.microsoft.com/en-us/library/gg412729.aspx.
First, we are prompted to install Visual C++ 2008 Redistributable.
Once installed, Setup dialog box appears.
Click Install and accept the License Agreement on the next screen and click OK. At this point, Lync Server Code Components will be installed and the deployment wizard will appear.
Click “Prepare Active Directory”
***As you can see, some options are “dimmed”. This is because the preparation requires strict order and the wizard help us to follow it.
Click the only available option to prepare the Schema.
***Have patience. It might take minute or two. Wait until the “Finish” button is available. I strongly advise you - always examine the result of the any action you perform via the wizard. In our case, the schema preparation was successful.
***In my case I have only one Domain Controller and will not worry about Replication. However, if you are deploying Lync in Production (which means you have more than one DC), always wait/check if the replication was completed.
Now “Prepare Current Forest” button is available. Click “Run”.
***In my case, I will prepare the “Local Domain”, since it is the only domain in the forest.
Verify the successful completion and click “Finish”. Prepare Current Domain is now available. Click “Run”.
***Shall you see an error on any of the above steps, do not run to Google and apply every “fix” you might find. Ask the community first: http://social.technet.microsoft.com/Forums/en-US/category/ocs. Here you will find first hand help and the risk to wreak havoc in your production environment is much lower.
Exit the “Deployment Wizard” and eject the media from your Domain Controller – we are now done.
***Another advice: Right now, use “Active Directory Users and Computers” console and add your account to CSAdministrator” group. By doing so, later you will spare yourself the question “Why I cannot access Lync CP (Control Panel)”