Lay your iMac face-down on a soft, clean surface as shown.

Be sure there isn't any dirt or debris on your work surface, as it may scratch the glass panel on the front of your iMac. We recommend placing a towel between the iMac and the work surface.

Loosen the three Phillips screws securing the access door to the bottom edge of your iMac.

All three screws will remain captive in the access door.

Remove the access door.

Gently slide the black plastic RAM pull tab out from the RAM slot.

Pull the black plastic tab away from the bottom edge of the iMac to eject the module(s) on that side of the RAM bay.

This may require a bit of force.

Slide the old RAM module(s) out of their slots in the RAM bay and set them aside.

Repeat the process in the previous steps to remove the RAM module(s) from the other side of the RAM bay.

When installing new RAM modules, it is important to orient them correctly.

Be sure the small notch cut into each RAM module (shown in the first picture) mates with the protrusion in each RAM slot (shown in the second picture).

Your iMac has four RAM slots. Be sure to slide each RAM module into its slot horizontally. This will prevent getting the modules stuck between two of the adjacent slots.

Once you have oriented the new RAM modules correctly, gently slide them completely into the iMac and use your thumbs to firmly seat them in their sockets.