Note: Your computer has two memory slots: one under the keyboard and another on the underside of the computer. If you install a memory in only one of the two slots, install it in the slot located under the keyboard.
Please perform the following steps as shown in the pictures below.
Memory (in the slot under the keyboard) installation
When installing: Insert the notched end of the memory into the socket. Press the memory firmly, and pivot it until it snaps into place. Make sure that it is firmly fixed in the slot and does not move easily.