Where do I assign GUI scripts?

I’m making a game using the GUI section of Unity, and I’ve written a script using calls to GUI.drawTexture and similar, but where I’m not sure where to actually assign the script so it will be executed! Thanks in advance - I know this is a bit of a stupid question.

In the OnGUI() function. It doesn’t really matter where the script itself is (on the main Camera is traditional), you just have to put all your GUI stuff in OnGUI() or it won’t work.