vCenter Server does not include TFTP server, so you need to install third-party TFTP server as well and store the boot files from your vCenter Server.

To access those files, navigate to the Configure tab of your vCenter Server, select Auto Deploy, and Download TFTP Boot Zip:

As the TFTP server, you can use some free tools such as Pumpkin TFTP server available at http://kin.klever.net/pumpkin/binaries, SolarWind TFTP Server available at http://www.solarwinds.com/free-tools/free-tftp-server, or Tftpd32 available at http://tftpd32.jounin.net/.

When you boot a new server, it gets the IP address from the DHCP and connects to the TFTP server through Option 66 and Option 67 specified during the DHCP configuration. Your new host will be available in the Discovered Hosts tab of Auto Deploy configuration, you will be able to see the host with an assigned IP address, or it will be automatically added to the inventory based on your deployment rule.