I am just extremely thankful for this great support guide material.
It was very clear to me. I shaped an empty cleenex tissue box, left only a little margin. I draw the bottom with a pen 24 squares numerating them from nr.1 to nr. 24, for the screw, one square for one set(or picture) of screw. I achieved to put the screw in exact order as I removed them, it went back, same screw into the same place. Not because I am that great, but because the guide is precise, and The Good Lord guided my hands to do this task with no errors.
The fan by the way was in perfect condition (late 2007 MB 3.1), almost no dust.
But it was a useful experience, for future possible issues.