Almost anything will work, but if you're inexperienced you might as well just go to OWC, find your exact Mac, and buy their standard OWC RAM for it.
It's guaranteed to work in your exact model of Mac, comes with Mac-specific installation instructions, is high quality (haven't had a stick fail yet at home or work), and has a lifetime warranty that they will probably be around to honor. The prices aren't at all bad compared to any decent brand, either.