[NTG-context] Text in Margin

In a textbook I am looking to place a large left margin at every page of each chapter. At left printed pages a left margin and at right printed pages a right margin, so like a double sided construction. In this margin I would like to place: 1. Keywords and small descriptions to emphasize some text from the textflow 2. Figures 3. An expansion of a table that is placed in the main textflow but that needs to cover a wider range then the text area so it expands into the margin What is the the easiest way to achieve this? Jeroen