After extracting them you need to place the images, .meshs, .material files into the "items" folder (Media>>Items)
There SHOULD be a .items file with the download. Place the .items file in the Feralheart folder, not any of the folders within and replace the existing one.
Just to let you know, if you are going to download more items you will need to open up the .items file and place the codes in it so you dont lose your previous ones.