If you damage the computer, then yes, you will void the warranty. Read your manual. They recommend that you take it to an apple tech, then they give you 4 pages on how to install it yourself. Its not as hard as it sounds though, even if you have never installed ram before. The main challenge is that no matter what, you want to be patient and gentle through the process, however a little bit of force is needed to fully seat the ram into the socket. You need to use the right #00 phillips screw driver and when you put the screws back in, don't torque them to much, just enough to keep the ram cover plate snug to the computer. Once you realize how easy it is, you wil be glad you did'nt pay 50 bucks for it.
Good luck