It is really easy to put the pieces together. The most delicate thing is putting the cpu in the motherboard, and that is not hard at all. Outside of that it is just pushingthe memory into the slots, screwing down motherboard, pushing video card into slot, screwing down hard drives/optical drives, screwing power supply and hooking up cables, hooking up cables to hard drives and front case ports and then installing windows.
There are tutorials on this website and many videos online.