I’m home brewing KibbleTasty’s Spiritsworn subclass for the fighter(x) and I’m having trouble with the 7th level ability as follows: 

Empowered Strike

Additionally at 7th level, you gain the ability to empower your weapon with its aspect. When you manifest or change the form of your Spirit Weapon, you can expend a 1st level or higher spell slot. When you do so, the first time you deal damage with it before dismissing or changing its shape again, it deals an additional 1d10 damage of a type matching it's aspect (fire, cold, lightning, psychic, bludgeoning, or respectively).

Any help with clarification on how to home brew this (modifiers, class feature options, actions?) would be appreciated.

Add a “General” Action for the 1d10 damage roll and don’t specify a damage type. Set it’s “activation type” to special, and designate it to display as an attack.

Thanks !

Happy to help.