Help ! Qin: the warring states requires PowerCards.js

Hello guys, I'm very please to use Roll20 regularly, its very convenient and perfect for long distance role play ! But today I'm facing a little issue. I am playing Qin: the warring states  and there is a specific character sheet for this game. But I cannot use all the features of it (especially the rolling dices). On the description of character sheet there is this information: " Requires PowerCards.js for the sheet rolls. Ensure that this is loaded in order to function properly."  >> I have no clue about the meaning of it, I have no clue what is an API, could someone explain me how to load this "PowerCards.js" ? Thanks !

At Roll20's Pro subscription level, you get access to user made scripts, like Power Cards. It sounds like this sheet is made to be only fully usable for Pro users. Is there a configuration setting in the sheet to fall back to non-script rolls? Edit: I just checked and there isn't. That sucks.