What I want to write is an addon that let's you move the minimap mail icon. Either by clicking and dragging or by showing a slider when you click the icon.
I'm not totaly clueless. I did some simple addons like a year ago and have experience with programming. What I don't know is where to start. Where can I find documentation, tutorials etc. I'm having a hard time finding anything useful at all.
Detached MiniMap Buttons (aka DetachedMiniButtons) lets you move all minimap buttons, including the mail icon, so perhaps looking at its code would help you?