I was just looking at the CentOS Wiki at https://wiki.centos.org/HowTos/PXE/PXE_Setup, and it's pretty seriously out of date. It neglects the existence of the "syslinux-tftpboot" RPM, and the hand editing of xinetd config files for tftpd ignores the availability of "chkconfig" and "service" to manage that service.
For more sophisticated users, it doesn't mention "never, never, never set your default menu to install an OS by default, because you *will* accidentally wipe servers that select PXE boot first before local disk as their boot media". Nor does it mention the difficulties with PXE and NAT based virtual host, nor how to verify the TFTP service's basic operation, nor the difficulty of maintaining multiple PXE configs when the main rsync mirrors only publish the most recent CentOS.
I'm happy to add that sort of thing to the wiki, but I'm finding the "Set up an account" page confusing. Is "FirstnameLastname" supposed to be your mandated login name?