Ensure that the retention latches are open and then insert the DIMM straight into the slot, pressing down on both corners at the same time until secured by the latches.
Use the same procedure to install any remaining DIMMs.
Install the side cover. Position the bottom of the cover over the edge of the chassis.
Rotate the cover down while aligning the tabs on the cover with the slots in the chassis.
Slide the cover forward until it is secured in place. Here is a closer look at the cover tab and a slot in the chassis.