How do I put my contols back the right way?

while Useing my classic petrol 35s lawn mower yesterday the bit that controls the engine fell off. I think I have found all the bits, two small bolts a bigish spring,and the metal brcket bit they all fit into. But I haven't a clue how to put it back together. is there a place I can get some sort of drawing so I can see how it is done?