To start with, you may want 7-zip so that you can simply open the .zip. Once you have opened the .zip from that download there will be two folders, open the one named "map" and copy those files into C:\FeralHeart\exports. Then open the other folder from the download named "grassmesh" and copy the "grass.object" file into C:\FeralHeart\media\objects. Lastly, open the folder named "grass" and copy those files into C:\FeralHeart\media\my_objects.
I would have to say that this download is not set up to easily understand, but there you go. =)
Edit: And as stated before, the default portals are extraordinarily hard to see... you might have just missed it by chance.