Compaq Evo D300 Hardware Reference Manual page 20

Hardware Upgrades
2–8
3. Open both latches of the memory module socket 1, and insert the
memory module into the socket 2.
Installing a DIMM
Begin by installing a module into the socket nearest the
preinstalled module, and install the modules following the
numerical order of the sockets.
A memory module can be installed in only one way. Match the
notch on the module with the tab on the memory socket. Push the
module down into the socket, ensuring that the module is fully
inserted and properly seated 3.
Hardware Reference Guide