How do you make a progress bar using Common UI Plugin?

So I’m using the Common UI plugin and I’m trying to create a few progress bars, but i’m having a hard time figuring out how to set them up to get them to extend to the right by a set amount. I can get them to fill all the way to the right, or I can get them to like a minimum size, but not the size I specifically want. Anybody know what the general layout and settings should be? Currently I have Overlay → Horizontal box → Vertical Box → progress bar + progress bar. This gets the bars to sit vertically one on top of the other, but now I need to extend them to the right.

This will answer all your question a little more.

But my question is, every single piece must inherent from activatable widget? A progress bar, for example, or just the main widget that holds all the pieces?