It's not hard to set up, if the BIOS has a "PS/2 port emulation" setting for the USB. That will at least allow for keyboard + mouse (but not scrollwheel) to work in the Windows installer.
But remember, you cannot use USB, until you get the xHCI driver installed. Which means, also, that you cannot put the xHCI driver on a USB stick and plug it in to install it.
I've heard that if you install Win7 from a SATA DVD-RW/ROM, then after you finish installing it, you insert the mobo's CD/DVD, and install the xHCI driver that way, it will work.
The method that I've personally used, is to make up a UEFI-bootable Linux Mint 17.3 USB stick using Rufus, and then boot off of it (after installing Win7 64-bit off of DVD), and then Linux has no problems with xHCI, so USB is usable in Linux, along with the ethernet, so connect to the internet via ethernet, and then download the drivers for Win7 off of your mobo mfg's site, directly to your HDD/SSD that you installed Win7 to, using Linux to write to that drive. When finished downloading, shut down Linux and re-boot into Windows. When in Windows, just double-click and install the driver file(s).
Once the chipset and xHCI drivers are installed, then you can use USB sticks normally.