How do you use that condition function or any similar condition that seem to require an object reference?

I was trying to do a perk similar to Armsman but adding a condition on the item's tempering level. On "mod atack damage" entry point there's a condition tab saying "weapon" but I guess there I can only put conditions on the base type. How to I put reference conditions like GetItemHealthPercent? If I put it there it seems to always return 0.