I might be able to help...
If it's a ZIP file then you'll have to extract the files inside first. Inside * Downloaded file name here* there should be a Readme, in the readme there may or may not be the list of items inside the pack, [I'm not entirely sure] but you'll need that list... Inside *file name here* [you may need to click around the folders inside] should have all of the items, you'll need to take those items and put them into "local disk c - FeralHeart - Media - Items." And the list i mentioned eirlier? You'll need to copy that and paste it into the file entitled Items inside the Feralheart folder.
There you go, hope i helped! ^^
If it's too complicated [I'm not too good at explaining things] there are lots of video's telling you how to do it.