HaloMods "Classic" Read-only Archive

I followed the ghosts turret making tutorial, and everything worked except when i tried to make the collision geometry tag in tool, nothing happened. In the tutorial he copied his .JMS model for the turret and put it into the physics folder and said he could do that because " when I was creating the model I was following the sealed world rules". I'm guessing this is where I went wrong.
Does anyone know how I can make the collision geometry tags or where I went wrong?

u could just make a basic outline of the turret for the collision geometry rather than using all the detailed parts which would make it less likely to get errors.