Nexus Mod Manager Help for modding Far Cry 3

[Nuka Cola]

Nexus Mod Manager Help!
Ok, so I rescan my games but the problem is it shows me games that I haven't even bought so of course they wouldn't be found in my computer, but I am trying to add Far Cry 3 onto Nexus but I don't know how to add a new game since it doesn't show up as a game I own, solutions?
I am pretty new to NMM so far, and Skyrim is the only one that allows mods to work here. I was told that there was not a option to do it through NMM so I was wondering if there wasn't another way to do it. there is some pretty good mods out there of Far Cry 3 and I'd hate to miss out on it.

[Winter Grass]

I am experiencing the same problem has anyone figured this out?