Installing laptop memory:

Turn your laptop over and remove the small screw to the memory door.

There will most likely be more than one door, you may need to open more than one to see which one is for the memory if it does not say what each door is for on your particular laptop.
(make sure the laptop is off when doing this)

Your laptop may have one or two memory slots. The image below shows TWO slots, one has memory in it and one is empty.

If you have an empty slot, just slide the appropriate memory chip in at a 45% angle. 

Low it flat allowing the ejector clips to lock into place

Replace the laptop memory compartment cover and insert the holding screw.

** If both slots are full and you are upgrading (e.g. you may have two 256mb chips totaling 512mb memory) then you will need to remove one or both to insert the new higher memory.