Dell Inspiron Small Desktop (3646, Mid 2014) - Manual (Page 17)

Procedure
1 Align the notch on the memory module with the tab on the memory-
module slot.
2 Insert the memory module into the memory-module slot, and press the
memory module down until it clicks into place.
NOTE: If you do not hear the click, remove the memory module
and reinstall it.
1 memory module 2 memory module slot
3 notch 4 tab
Post-requisites
Replace the computer cover .
17