System -> Hotkeys -> Page 2. -> Toggle Tips Display (Basic/Adv.) -> Allocate to any hotkey (I suggest F6)
then scroll over the skills again, it should tell you to hit the hotkey to view details. Commonly, the details are just what the skill stats are, such as duration of a buff or % of an active skill, but some of them give additional descriptions, which is what I put in as notes on the wiki.