Problem with the Container width

At this moment I’m following the Webflow portfolio tutorial on Youtube
(Creating a custom portfolio — Intro (Part 2 of 8)) 3:15 / 8:58.

Now I want to give the ‘Hero Right’ a width but that’s not possible. When I try I see the next message: Webflow automatically handles the container width to make it fit different devices. But I can’t see my image when I publish the site.