Add a row on new page

Evening all,

I've created a new page on Page Builder, which has two columns.  I now want to add another box below these columns, but the stretches across the whole page, so effectively a third 'column', but BELOW the other two rather than next to them.  Is this possible?

Cheers

Phill

I would love to be able to do this as well, Hopefully someone out there will be able to assist us with an answer.

Bumping this up, I think a lot of us would like to be able to do this.  Anyone have any suggestions.