I try to describe the idea of repairing vehicles. Most of us know what it takes to manufacture spears (this is a logical sequence of actions , even without reading the manual ) . But transport - is a complex mechanical device . If put on wheels can still be easy, then fix the engine without knowledge is not possible . The idea is that you can find the manuals for repairing cars. Assume the vehicle is divided into 20 pieces to be collected in the sequence. Well, this sequence will be described in just such a manual . The more complex the device, the more parts it have. And yes, of course you can try to repair the engine randomly and it will hold, but will not work.