You’ll need to copy the engram to your mod folder and edit it, you’ll need to copy and edit the primalitemstructure file as well for the torch and you’ll need to remap the engram in the primal game data. See below.
As far as the structure itself goes, I think you’ll need to add it to the additional structures to place array also in the primalgamedata file.
I do not know if it would work for remap items… I believe that may be more for consumables and things. I don’t know for certain though as I hate core-data mods and stopped working on them.