update problem

[Arsinowey]

Hello,I have a question and you're the first person that I feel will not make me feel like a dumb-ass for asking the question I have...
OK,I bought the game from Amazon,it wasn't an online code for Steam,I didn't know what Steam was back then lol...anyways ,I know where the thread is to download the patch,I just have no idea how or where the game is in my computer or how to make sure the patch is installed into the correct file...
PLEASE HELP !! I'm somewhat technologically challenged !
Thank you in advance if you're able to help!