global macros and how to use them?

Hello, I noticed global macros are new with the new update but I cant find any documentation anywhere on how to use them. All I know is that you push a button on your razer device and it will read it as Shift+Ctl+6 and you can assign a macro to that, but I am like, thats what you do anyways with the buttons and the macros.....?? I dont get it can someone please explain to me how to use them and what they are for please? Thanks!