This will be hard to explain. The 2 silver cylinder caps and the bolts go on the manifild end, the end of the bolts are housed in the caps. The caps slot in the holes at the end of the manifold facing the engine. The springs go at the cat end, and the brass coloured caps go on the end of the spring all held on by the little bolts. IIRC there are 2 types of 2 different washers and I cant remeber where these go without looking but Im sure they are at the cat end.
The round gasket ring should fit nicely in the cat.