You probably want to check out Yocto instead:
https://www.yoctoproject.org/ There's a lot more info on OpenEmbedded and the Yocto project there. This is really interesting stuff for embedded Linux in particular. You could build a desktop distro with it if you wanted, but that's not really the point of the project. It's more for rolling your own Linux distro to run on small board computers (Pi, BeagleBone Black, etc.), set top boxes, etc.