I ordered a Macbook Pro 2011 and the same - after it arrived (with 4 GB RAM) and I tested shortly, if they ever had as far as - built this RAM kit with a total of 8GB RAM.
After that I started the system and looked to see whether everything was recognized and it's all great. Instructions for installation can be found in the operating instructions for Mac or the Internet to video portals and ifixit.com. The installation is the difficulty here is no problem, after you've looked at a manual. Only when all screws heard this feeling because they are very small (and may not be overtightened), but nevertheless relatively fixed should be screwed again. As I said -. With a little feeling ... pretty tight .... but do not overdo it (with such a fine mechanics screwdriver you can it but eh not really overdo it (unless you take the pliers with it (what helped me in solving, because blue threadlocker is applied)).
