Problem adding custom card to Lovelace

I wanted to use this card for a charging setup for Mercedes that a fellow forum member has made:

But I have a problem, because even if I have put the js file in .homeassistant/www/ and added it to ressources, it just won’t work, it says the custom element doesen’t excist. Is there an error in how I have added it to ressources? I have tried both /community_plugin/dual-gauge-card/dual-gauge-card.js, which I suspect is for Hassio and /www/dual-gauge-card.js as the URLs in ressources, but nothing seems to work. Here’s a couple of screen shots: