Added columns on a row, but how do I access the row part?

Added columns on a row, but how do I access the row part? I can no longer seem to click the row part so I can't edit it. I can only click the columns on that row

on the left in the "Overview" click on "ROW" then you can edit the attributes.

if you want to add more into the row - drag it in the Overview on "ROW"