New to WoW, appreciate the help

Hello fellas. I'm a ret paladin, and having some questions about macros. I searched on internet about them, but honestly, didn't understand too much. What I understand is you can use 2 spells on the same time, being benefit for you. But I don't know how actually I need to utilise macro. Mainly I wanna use them in PVP and learn the strategies about this.
Another thing i'm curious, is anywhere a guide with daily quest on H? Also, quest you recommand to get more gold, I'm trying with professions, but I want something "consistent" to make gold/hour.
Thanks!

Okay, so macros, when formatted properly, can achieve a lot of things.

For paladins, macros specifically for arenas is where you want to shine.

I normally stick to 2v2, as I just havnt quite got the hang of 3v3 yet.

As Ret Paladins, we get a lot of Art of War procs for instant Flash Heals. This is a great thing not only for you, but your teammate. That instant flash heal could be the difference between them living or dying. So, I have a macro that is just a flash heal that targets myself, and one for my teammate.

Macro for myself: #showtooltip /cast [@player] Flash Heal (Rank 9)
The show tooltip just shows the Flash Heal icon, nothing more. Now, we tell the macro we want to cast a spell, but the target is myself. Without ever deselecting my current target, I get a flash heal on myself.
For my teammate: #showtooltip /cast [@party1] Flash Heal (Rank 9)
It does the exact same thing as the macro above, but it auto targets the first party member for the flash heal.

Another useful macro is: #showtooltip /cast [@focus] Repentance
Whoever you set your focus too, that is who will get incapacitated. This is great for two reason, you never have to move your mouse to select your target then hit a keybind to cast. You just hit a keybind. The other great thing is you dont swap targets for your enemy to see. Sometimes, enemies will see you swap targets and get ready for the crowd control. This prevents that and can catch them off gaurd.

There are endless macros out there. Are there some you saw you want specific explanations for?