Help with an inventory

Im trying to make an inventory, that will be used like adrenaline, for some special artifacts, the problem, is i dont know how to make it work

The line for the adrenaline is Instigator.Controller.Adrenaline

But i dont know how to find out this one, every time i try it, it says it dont exists, but i already compiled it before, and it works perfectly, but the artifact dont accepts using it, its says it wasnt found

Can you tell me how to find the line? xD

Well, now it works, but now one problem, how do i set the max amount for that inventory? because it always stays in 0