1st unzip the folder>open gecko19 folder >open another gecko19 folder>open HBC folder>drag the Gecko19 folder in the root of your sd card. The folder you drag (wich is the Gecko19) should only have 3 files in it (boot.elf, Icon and Meta). If it doesnt, your using the wrong folder.
INFO: GeckoOS is a App for Wii wich lets you hack. U need cheats for GeckoOS for the Cheats to work ( see more here http://wiibrew.org/wiki/GeckoOS#Ocarina )