Well, I'm not sure of your maximum amount, but I do know (after dealing with such matters just yesterday) that the RAM cards should be labeled (I have 2 new 2GB ones in my computer now, and they're both labeled).

As for installing, simply turn off your computer, preferably unplug it (I don't know if this is necessary or not, but I was told to remove the battery from my laptop as I did this), and locate the RAM card(s). Depending on how many slots you have, you can either install a new card or remove an existing one and place a larger one in. It's not hard to do, really. Upon startup, you'll be told that the memory has changed, simply follow the direction to continue. (At least, that's what happened to me.)