It depends. Some of the more recent mods you can unzip them on the mods folder and voila, while others you have to convert them so the game can read them. In those cases, those mods are from a previous version, Like Legacy (1.x) and "Demo" (2.x I think). How to convert them is through an executable that some members have linked previously on this thread.it keeps saying no mods found
Edit: I forgot to mention: sometimes the mod itself can be divided as an album or as a single, depending on how it's bundled. You may or may not have to switch between those two on the mod screen to make it appear.