Never worked with wood before but want to build a platform bed frame, help?

What's hard is that its king size, so I'll need at least 2 large pieces of (ply?) wood. I'm wondering if those two pieces can be joined together and placed onto a base? If so, how big must the base be? One thing I don't want is to have cutouts and slats because it seems complicated and I could just buy that. Is my concept of a large slab of wood (made up of 2 smaller pieces) feasible? Any good site that would help? Thanks!