Running Windows on Mac Pro - Teach Yourself Visually Complete Mac Pro - page 998

Click Choose .
In the Open dialog, click the ISO file.
Click Open .
Click the disk to which you want the Windows installation files copied.
Click Continue .
When Boot Camp Assistant warns you that the drive will be erased, click Continue
(not shown).
Boot Camp Assistant creates the installation drive. If OS X displays a message about
allowing a new helper tool, type your password and click Add Helper .