Everything is under the First person character at least but AssultRifle is not under Items ORG-hand_R but instead under the other Item folder.
I will delete everything and start over again, the problem is I follow the tutorial videos but somehow it doesn't work for me.
Started a new scene and now I have the same problem I can't build the item.
Maybe something is wrong with my installation.
Because I installed the assets Third person and First person separately I was told that was the same as Ultimate controller.
But I can't add UI setup and Virtual Controls setup so maybe it's more stuff that's wrong.
I can't even add one weapon. I was going to add 10+ weapons and that just feels impossible if I can't even add one by following simple guides.
Later I will try and install just Third person OR First person asset, not both and see if it works.