I presume you're using Max or blender? If so then you can start by making a very simple import in outerra just to get the ball going. First export a FBX of your model with max or blender. Then in Outerra, open the FBX importer ctrl-f7 . Click ''open FBX'' , select your model fbx file then hit ''create pkg'' and voilà!
Reload the game and you should be able to open your model as a static object ''F7''. The textures wont show but you should see at least your model. If all goes well then you could try to add the steps that PytonPago mentionned.
