I think you need a kind of two-pronged tool a bit like circlip pliers to insert into the little holes on the winder cap(s);then twist off. If the flash sync socket (on top of the prism) is like my OM-1, it looks like it's a similar affair to unscrew it. You need a tool with two blades to slot into the two open-ended slots on the outer ring. You might just be able to do it with a couple of very small screw-drivers, holding them together and gently twisting anti-clockwise. You need to be careful about scratching.