Every row, column, section, container and element has a copy tool and a cut tool in its drawer. Once something is copied, a paste tool shows wherever it can go: a row into a column or a section, a column into a row, a container or an element into a column. A copied row or section can also be pasted from the toolbar, with the on the right: click it, or drag it to where the copy should land.
With the keyboard: click a node - a row, a column, a container, an element, or a text - on its background or its drawer, and it becomes the target, with a dashed outline. Ctrl+C (⌘+C on a Mac) copies it, Ctrl+X cuts it - and the target goes to what held it, so a paste puts it back - and Ctrl+V pastes what is copied into it, at its end and in the level it lacks: a row pasted into a row goes in a new column of it, a column pasted into a column goes in a new row, and a container or a text pasted into a container goes in the tab or the item it shows. A section goes after the block the target is in. While you are writing in a text, or have text selected, the keys copy and paste the text as usual. Escape, or a click outside the editor or on the canvas outside any node, clears the target.
What is copied is kept in the browser, so it can be pasted in the other editor, after a reload, or in this page open in another tab.
Then paste it into a column below, or into the other editor. Its id is renamed in the copy, so links to it keep working.
An element: copy it into another column.
A column to paste into.
Another one.
And a third.
Paste here what you copied above.