Here is a layout for Rock It! Ceriatone Amp

Well layouts are for assembly.  They are intended for those who are familiar with the circuit and only need to know what goes where.  They were something employees on the assembly line used.  Often wires are left out because to is an assumption that the person assembling an amp knows some basics about amps or the circuit in general. 

They do not substitute for the schematic, which is the actual circuit drawing.  Nik doesn't supply schematics, which I find little of a problem. 

There are schematics for the Trainwreck Rocket, which the Rock it! is based on over at The Amp Garage forum.  You'll have to register to see and download the files, but they are very handy.  Plus, there are lots of Trainwreck discussions about the nitty-gritty of the various models.

As for the circuit, it isn't complex, it just looks that way on the layout.  Trainwrecks aren't complex amps, they are just tough to build right because when you have so much gain, it's asking for noise issues.  You want complex, look into a Fender AB763 circuit, or Soldano SLO.  Your confusion implies to me that you may not be up to building an amp yet,  Perhaps you should start with a simpler design like a Tweed Champ or Tweed Deluxe clone.  Also, I recommend the Tube Amplifier Handbook by Dave Hunter, it'll give an idea of the basics of what each component does in an amp design in general.