I found some photos I took to help me remember the disassembly steps.
This is after removing the mount and aperture ring. I vaguely remember having to loosen some trim rings like the one with the red dot and arrow on it, and the larger one with focal length markings, to access screws hidden by them. A good source for the small common screwdriver for those tiny slotted screws is an eyeglass repair kit. There's a bearing that makes the aperture ring click at all the stops and maybe another one for the macro ring, so watch for those.
This is an assembly removed from the rest of the lens. I think removing the larger crosspoint screws just below the focus ring in the previous photo allows this section to pull out. I've also remooved the silver-colored slotted ring and some more screws visible in the last photo. The rear element is pointed up here and the assembly is resting in a lens hood for photographic purposes.
That rear assembly comes apart further to access the aperture blades. This is the part above (further from the lens mount) the aperture blades.
This is the lower section with blades in place.
And the same piece with the blades removed.
With so many elements, you can't see the actual surface with fungus, so you'll have to explore a bit. Many times the fungus is just above or below the aperture blades, but that is less likely with this lens because the aperture blades are in their own small assembly. The subassemblies in these photos have several elements in them, in tubes that unscrew in sections.