1-let us assume that we have CU1 package located in “C:\SQL2012Updates”,
SQL server 2012 is installed from E: drive.
2-The command to install SQL server and CU1 will be
setup.exe /Action=Install /UpdateSource=”C:\SQL2012Updates”.
3-Product Updates screen will display the KB number of the CU package to be installed.
4-Ready to install screen will highlight the version of cumulative update to be installed.
For more details about SQL server 2012 product update see:
http://msdn.microsoft.com/en-us/library/hh231670.aspx