Lenovo 3000 C305 All-In-One - Manual (Page 35)

Chapter 7. Replacing hardware
33
5. Gently slide the cover toward the side of the computer, and then
remove it.
6. Push out the latches on both sides of the memory socket to release the
memory module 1 and gently pull the memory module upward to
remove it from its socket 2. Both memory modules can be removed
by using the same procedure.