Splitting documents

I have my different documents that make up my thesis on my corkboard. How can I split up a document because it now contains two chapters which I need to change the order of in the thesis?

Click at the heading where you want to split a document.
Right click and choose EITHER: split or Split using heading as title.

I usually choose the split using heading as title. You can change the order of the documents by dragging and dropping the index cards on the corkboard