always detach the flexible cables with utmost care.
as they come into view, detach them. the connectors soldered onto the boards are FRAGILE, never force anything. they will easily release the flex cables when you flip up the lock part. its usually a different color than the body of the connector.
be gentle, persistent. use plastic tools
NEVER use metallic cheap screwdrivers, pryers or knive edges! get a good set of Wiha screwdrivers too.
the process is sequential, once the back cover is off, remove the cpu board, there's flex connectors to release.
there's a really fragile wire attached to the WIFI thing (or microphone) use caution , small and easy to damage
remove the sensor board. there's three screws with tough springs, that keep it aligned, with some terribly hard fixation glue to prevent them from moving. some other screws also. try to remember how may turns you use to get them off, that will allow you to get the sensor somewhat back into alignment when you put it back on.
once that is off, the shutter module is right there.
on reassembly, the sensor plane may be a fraction 'off' , but if you forget the turns, try to keep them all the same, that should get it within useable tolerances
(the case and other parts are made with very tight tolerance to ensure accurate assembly from the start)
most people wont even notice the loss of aperture/focal plane error if its a few degrees out of whack.
professionals will complain, and they can pay to send to a professional repair at professional prices.