Changing Game GUI Problems

[Izayoi]

So I have a GUI downloaded and I looked at tutorials but I don't really understand, still.

1.) Where do I put the files? Do I put it in "game", "images", or should I create a new folder to put the files in?
2.) Exactly how do I know where each file goes? I did open "screens" and find the "yesorno" and I edited that to say "yes_hover.png" (which is the title of the file) for yes. I didn't save it though in fear I'd break something.
3.) Exactly how do I edit .PSD files?

I'm sorry, I must sound really stupid and noob-y.

[Imperf3kt]

Can you link to what you downloaded so we may know exactly how to answer. Right now there are a million ways to edit the GUI and without knowing specifically how someone else did things, we cannot give any guidance.

[Izayoi]

I downloaded the Cherry Love theme linked in this post.

[Imperf3kt]

I'll take a look after work, but from a glance at the post, it looks like the pack uses the legacy GUI , so you cannot use it with the new GUI without modification, though it should still work as is.