For the items, you put all of the files (except the ReadMe) into FeralHeart>Media>Items. Delay's item pack already comes with its own items.cfg, so all you have to do with that one is drag Delay's items.cfg into the main FeralHeart folder and save it over the old items.cfg.
Tetsu's items don't come with their own items.cfg, so after you've already replaced the old items.cfg with Delay's and put the items (from both Delay's and Tetsu's item packs) into the FH items folder, open Tetsu's ReadMe, open the items.cfg in the main FH folder, and copy the codes from Tetsu's ReadMe into the main items.cfg. All item packs pretty much work this way.
Good luck and have fun with all this stuff! If you need any more help, just let me know.
And thanks! I'm glad you like them.