I have a mods folder but what is the method for that?

So I want to get the tsunami mod but i'm worried that I will be stuck having a tsunami in my game for forever. (sorry if i'm being stupid I've never used PC mods)

Thanks. Also I am new to gta 5 mods and how do you disable a mod? Do you just uninstall it? When you install it does it automatically connect to gta 5?

I am trying to download mods. But just about every single one has a .zip at the end. Is there a way to download these mods without buying WinZip?