This link will take you to the assembly instructions for the $350 and $425 levels. I have assembled the exturder already so there is not much left to do once you get your system. Just some basic stuff and hooking up the wires.
Please make sure to cover up all the unused wires or terminal strips, with the wire nuts and electrical tape. Do not leave any contact exposed for safety reasons.
I may have missed some steps, so let me know and I can put more pictures up or explain more.