You don't need to install the video drivers before you can use the monitor. Just plug the monitor into the videocard and boot the PC.
The resolution will be horrible, but you'll be able to do everything you need to, like install drivers.
Every PC i've ever built, had no onboard video. You just install everything properly, including the videocard, then boot the PC and install all the needed drivers.
Before you install the videodrivers, install the motherboards, chipset drivers.... Then you can install whatever you want after that.