The reason why is not placing is because your copy doesnt have a structure itself, Cooying the primalitemstructure_mortarandpestle wont just do it. Type on search mortarandpestle and youll see this file with an image of the mortarandpestle with a blue bar in it, copy that to your mod folder, go into structure area and select consume Primal item Your File name, ex: PrimalItem_NewMortar. Then go into the PrimalItem_NewMortar and set on Structure to Build(ex.NewMortar). You dont need to add the item to the master lists, just add the engram in the additional engrams list, and in the additional Structures to place make sure is pointing at NewMortar not the PrimalItem file.