How do I unlock the little padlock so I can change "col-sm-4" to "col-sm-6"?

Hi -- I created a new design with the "blank" template.

I dropped a "Highlight > Highlights Phone" in place and changed the phone to something else.

Now I want the image to take more horizontal space, so I'm trying to change its "col-sm-4" to a "col-sm-6" but there's a little padlock next to the "col-sm-4" and I can't change it. How do I unlock so I can change this value?

Here's a link to a screenshot ...

You don't "unlock" classes. The class is set via the visual interface. Highlight the column, go to the upper right and select the options tab and you will see the Column Options. Click the little arrow next to the Width so you can see the width at all the breakpoints. From here, you can change the width from 4 to 6 (or whatever you want.)

You might want to watch the tutorial videos so you can learn how classes are applied in Bootstrap Studio.

Thanks for the help, I'll look at the tutorials.