I'm in the same situation. Having reinstalled WoW due to my computer being formatted, i do not get the Add Ons option at the character load screen. I havent changed the way i have always done it in the past and the files are found in their folder within the Add Ons folder. Blizzard's UI Folders already exist there and work, i unzipped to the desktop and put the mods in the correct path and folders.
Please help.
Thanks