If you like I have a demo environment with no Internet connection then you are also required to download the Configuration Manager 2012 prerequisites file prior to starting the installation.
- Open a command prompt with administrative permissions
- Navigate to .\Configuration Manager 2012 Install source\smssetup\bin\X64
- Run SetupDL.exe target dir (in my example SetupDL.exe D:\CM2012DL
- The total download size is 192 mb. and the total number of files is 14 with SQL Express and .Net Framework 4.0 being the largest files.