When you paraphrase another author's writing you rewrite their argument using your own words, phrasing and interpreting it in your own way.
Halliday (1978) claims that children develop their language by interacting with those around them.
orChildren develop their language by interaction with those around them (Halliday, 1978).
As you study and write your notes, don't copy chunks of text directly out of the book, instead always write your study notes in your own words (but note which book or article your notes were drawn from).
Once you have taken notes from the original source, work only from your notes: put the original article or book away.
Check your writing against the books and articles you are using as sources. If the words you've written are too similar to the original, you should try to revise your own wording.