Dell Inspiron 13z (N311z, Mid 2011) - Manual (Page 18)

18 Memory
5 Remove the memory module from the memory-module connector.
Replacing the Memory Module(s)
CAUTION: If you need to install memory modules in two connectors, install a
memory module in the connector labeled DIMM A before you install a memory
module in the connector labeled DIMM B.
1 Follow the instructions in "Before You Begin" on page 9.
2 Align the notch on the memory module with the tab in the memory
module connector.
3 Slide the memory module firmly into the memory-module connector at a
45-degree angle, and press the memory module down on both sides until it
clicks into place. If you do not hear the click, remove the memory module
and reinstall it.
1 memory-module connector 2 securing clips (2)
3 memory module
1
2
3