The first links should show you the different versions of the phone (ATT, T-mobile, etc.). Choose your phone.
XDA has tons of useful information about nearly every phone out there. Plus you can make an account and ask questions about your phone to other people who actually own the same phone as you do.
I have the GS3. I can’t imagine there’s that much of a difference between the two. The only thing I can think of is be sure you read all of the app permissions when downloading apps from the Play Store. Some of the apps don’t necessarily need all those permissions such as location if it’s just a game.