twenty20 with x theme and cornerstone

Thanks for you help,
I’m using X theme.
I have installed and activated the plugin.
When I go the classic wordpress edit I see the button for “Add twenty 20”. If I use this to add it to the page it goes to the bottom of the page.

In cornerstone I have created a table with sections, rows and columns and I’d like to use twenty 20 in specific columns. How do I do that in cornerstone. If not in cornerstone what is another way to do it?

Thanks!