page 'push' other pages ahead.

Hi,

I'm writing an 120 pages long document, but not in a chronological way, and I can't find a way to menage that words that I add, won't push all the other pages ahead. I'd like it to be - every page for itself, in terms of formatting and spacing. that way I can write something on page 55 and it will stay there, even though i've written something new on page 3.

sorry for the clumsiness of the question.

thanks