minecraft-expanded-datapack/assets/undeadm-m1/models/item/melee_weapon/diamond_warhammer_a.json

{
  "parent": "undeadm-m1:item/base_weapon_warhammer",
	"textures": {
		"layer0": "undeadm-m1:item/melee_weapon/diamond_warhammer_a"
	}
}