Launch the Parallels application on your Mac computer and wait for the Windows operating system to boot.
Insert the installation CD or DVD for the PC program you want to install in Parallels.
Press the "control" and "option" keys on your keyboard at the same time. This will display the top toolbar in Parallels.
Go to the "Devices" menu at the top of the screen and expand the "CD/DVD-ROM" submenu.
Select the "Connect to Default CD/DVD-ROM" option. The Parallels application will now connect to your Mac's disk drive.
Wait for the installation wizard to appear in the Windows environment and then follow the on-screen instructions for installing the PC program.