Editing Game tooltips

[Siku]

I recently started trying to make my own addons, and right now im blocked at trying to edit the tooltips that opens when you go over Strength, Agility and such, problem is the how to do it,

So far, i know i would need to hook the tooltip to edit it, but whenever i try reading about that, it explaisn how to hook an item, spell or buff, not really what i want.

I also checked in the framexml and what i want would be the PaperDollStatTooltip, but im not sure if its the name or what to do exactly with the info.

And by reading wowwiki widget api documentation, i guess that would go inline with using GameTooltip:AddLine (or AddDoubleLine)...

So, anyone out there could help a future author with how to get it all together?