How to build a motherboard
I hate nay-sayers more than anyone, and I'm all for undertaking difficult projects.

BUT

Designing and building a motherboard is Extremely difficult. Even if you already had great EDA software, and even if you already knew how to wire up the chips, the designing, building and testing process is about as hard as it gets.

It's a bit like asking: "I'm trying to do my own moon mission. How do I make gunpowder?"