Copying and pasting scripts

so this is kind of dumb to ask and i apologize i dont really get how scripts and macros work. I wanted to use someones arena ui script (smexxins to be exact), they have all the raw paste data for you to just copy and paste into macros, i just dont really understand what code i should be putting into what macro i guess? hope that makes sense.

It depends on what you want the macro to do, if it is simply casting a spell or attack, you would put /cast nameofspell. If your class allows it, sometimes you can cast multiple spells at the same time if they are instant cast, mainly these would be protection spells or buffs. In the cast that you want to cast multiple spells at a time, you would type /cast nameofspell, then press enter and underneath that type /cast nameofsecondspell.
As a rogue, i use my macros to combine my defensive spells together, and my burst spells together. so my code for my defensive macro looks something like this:

/cast Evasion
/cast Cloak of Shadows
/cast Feign

This probably isnt the best use for macros but this is what i did, and it gives you an idea on what to do. You can also add consumables to your macro like potions, scrolls, etc…, you would type /cast nameofitem.

If you wanted to copy paste the script for a macro, that’s literally all you do, there isn’t much you are required to understand, so im not sure what you are asking on that.