Attempt the following at your own risk!
It should be obvious, but you'll need a screw driver that will work with your equipment. A thin plastic card or something similar is helpful with prying the keyboard face off. I also like to have a small container to keep screws in, just to make sure I don't misplace them.Once you have your tools and your new hard drive ready, the first step is locating the screws that are holding your laptop together. Locate them and remove them.
Then you can carefully remove the keyboard. Flip the laptop back over and carefully pry from the edge, all the way around, using a thin plastic card for leverage.
For additional help, you can watch the video I made about replacing the hard drive, I show how to open the computer here: https://youtu.be/m-_m4fJMIZ8
Next, you'll need to remove all the cables connected to the mother board. Starting with the first three that you'll see when you lift the keyboard up, since they are attached to the keyboard (see video above).
With the keyboard removed, you can begin removing the rest of the cables. I like to start with the power connection to the battery in the back. Try to remember how all the wires are tucked in when it comes time to plug everything back in. You may want to document your work with pictures for reference points.
Now locate all the screws holding the motherboard down. I think I pointed them all out here, but I may have missed something.
With all the screws removed, you can remove the hard drive and cd/dvd rom. They both push out the the right:
Remove the ribbon cable if you haven't already:
Now you should be able to lift the motherboard out. There will be one more cable connected to the back that you'll be able to disconnect once you left the motherboard. You will have to pull the mother board slightly to the right, removing it from the USB mounting points on the case at the left, and then lift it out from the left side up, as the cable will be holding it down to the right.
Now you can lay the motherboard backside up to reveal the RAM
The black flap easily peels up to expose the memory.
They are each held in by a clip on each side. Pull the clips out side ways, and the memory should lift up and out.
Make sure when handling memory that you don't touch the connection plates. When you install the memory, you should be able to put it back in at the angle it came out, and then push it down. When you push it down the side clips should auto lock in to place with a click. The memory should then be secure.
Now back track your steps to re-assemble. :)