OK! we need create, create big cannons, create tank defenses, create cbc. Now the tank itself- when you assemble it a few things won't work: the cluch gets removed so place a new one and it's link. Then for the gearshift its link is borken so place the link under the block where the redstone torches are located. Then replace the mechanical arm to take items form both depots and insert in cannon mount and brass funnel. Auto big cannon