custom skins?

okay, this is my first time using custom skins. im using Wooxy. apperently its something well-known for people to use custom skins. and i just downloaded it, and everytime i go to drag and drop a compressed zipped file, it keeps on saying that a file is skipped. its really confusing, because there are SOOO many good looking yasuo skins on Leaguecraft, and i can't use them because wooxy keeps on skipping the files. any help on this matter?