Adding an Operating System to a Mac
Adding an operating system to a mac is roughly the same as using a windows. Except if you would like to boot from a usb during start-up if you have the operating system installation on the usb; you can hold down the OPTION key after the startup chimes or when the apple logo appears, this will take you to the start up manager and you can select what to boot from. In this case, it would be the installation disk or stick. From here you will be guided through the setup and able to customise your settings, date and time etc.
Note: The usb will need to be formated to contain a GUID Partition (the format needed for the installation disk to be recognised such as fat32 or ntfs for a usb stick).