I tried to find an option in the trophy room craft table but found nothing.so I went out and killed one thinking out might have an option to get mounted in your house but still no option for it. So how come they have life models in the hearthfire trailer then.

You have to build the trophy stands in the room, activate them and a list should appear showing everything that can be built on the stand, just check the ingredients for each statue.

As an example: Troll Statue is a Troll skull, troll fat and straw

That's great to know, can't wait for this to come to the PC.