You install downloaded maps like so:
1.) Follow the "read me" file if there is one (in your case there is none) and place the files in the places where it says or just place all the files into the "Exports" folder
OR
If placing the map files into the Feral Heart "Exports" folder didn't make it work right than try placing the files as so:
FHM files go into FH>Media>Terrains
FHO files go into FH>Media>Objects
FHS/FHW go into FH>Media>Sky
MP3 files go into FH>Media>Sounds/Music
Then restart the game
Hope that helps