If you're using Steam to download the mods, do so (subscribe), and you should find the downloaded files within the "ugc" folder here:
library(Important: your personal user's library, the hidden one!) / Application support / Steam / userdata / 146240701 (that might be a number just for me, yours being different?) / ugc
In this "ugc" folder you're going to find the mods you want under some ".civ5mod" files.
Copy them somewhere else (desktop?) and open that ".civ5mod" file with The Unarchiver (Mac) for instance, and move the whole folder you're getting from this into the "MODS" folder located here:
user (you) / documents / Aspyr / Sid Meyer Civilization 5 / MODS
Then launch Civ 5, select "Mods" in the very first game screen, select-enable the mod you just downloaded which hopfuly should be there (be careful not to check-enable all the showing mods, as they could sometimes conflict with each others, only the very few ones you need) et voilà...
My game is in french so I'm not sure about the names for the following of the operation, but just go with the regular launching mod procedure)
Let us know.
& Good luck.

(To load a savegame, after having exited Civ 5, you're gonna have to go through the "mods" menu from now on, in order to load any "modded" savegame.)

Thanks got it!

;-)