Just accquire some integrated circuits, solder them together and load up a program! It's really not computer science! Oh wait, it is..

I will not publish build instructions as it is a far to complex project to identically replicate and you would probably not understand my (arbitrary) design desicions in the background anyways. It is also not a very useful machine to build, but very useful for learning purpose.
I don't even have complete circuit schematics and i would not built the machine differently if i did it all over again! If you want to build a similar computer you will have to aquire skills in digital logic and computer architecture and make up your own design to fully understand it.