Left side, I think, there is a tear-drop shaped hole. The part of the spring that has a straight bit sticking off at 90 degrees to the hinge shaft goes in there. The bit that has a bent bit, starting at 90 degrees to the hinge shaft, then bending again to paralell with the hinge shaft, goes toward the lid.
Insert the hinge shaft, put the spring on the shaft, with the bent part on the bottom of the lid, then insert the hinge shaft into the shell (again, I think the left half) such that the straight part of the spring sits in the tear-drop shaped hole. The whole spring should fit into that hole. Now (after lining up all the internal parts) you should be able to put the other side of the hinge shaft into the small circular hole on the other half of the shell. Press the assembly together firmly, without pinching any wires, and bolt everything together.
PS: Don't forget to put in the spring and bead thingy in the tray, or you will have to disassemble and do this all again.