In order to enable PXE booting with your windows DHCP server, there are two options that must be set. These options are option 066 and 067. Option 066, Boot Server Host Name, defines the IP-address of the PXE Server. Pictured below.
Option 067, Bootfile Name, defines the name of the file to load to the terminal, from which boot starts. Pictured below.
Thats it! DHCP configuration is complete. If you have followed the articles Enable PXE on Windows 2012 R2 and PXE Structure on Windows 2012 R2 of this series, you should now have a fully operational PXE server.