breaking paragraph text

I have a document of 300 pages or so of flowing text which I wish to edit into chapters.

Ideally I would like to select the start of a line of text and place it at the top of a page where it will then stay without breaking the paragraph links, as in Word (this also maintains the word count across the whole document).

Alternatively, could I simply break the paragraph links? When I attempt this now with Arrange/Break Paragraph Text, all that happens is that a new page with an unlinked text frame appears, but the 'before' and 'after' pages are still linked, which defeats the objective.

The only way I've found to divide the document up is to copy it whole and then delete pages before and after the required chapter breaks and then reassemble them into one document, which is pretty laborious.

I'm sure I'm missing something really basic here.

Any help much appreciated.