Stack columns

How can I stack columns (for smaller screen sizes)? Much like the Landing page template, where one column appears on top of another when the screen resizes for small devices. I've been trying to recreate this but can't work out the settings.

From this to this

Essentially, I want to Make a Two Column Website Layout, Mobile-Friendly by changing to one column on mobile screens. Can anyone help?

I am having a similar problem- would love to know how you did it if you figured it out.

You do this by setting the column widths in the options tab. You need to expand the column width options and then you can set the width desired at different screen sizes. To have a column take up the full width of the row, you set its width to 12. If you want two columns in a single row, you'd set both of their widths to 6.

This is standard Bootstrap stuff. If you're not familiar with this, you need to take the time to learn how the Bootstrap responsive grid works.