Your chosen contents will appear in your book in the order you choose.
To Arrange the Sequence of Articles in your book: Click to highlight the Article in the left box and use "Move Up" or "Move Down" buttons to change the order. Repeat this until all of the Articles are in your preferred order.
To Remove an Article: In the left box, Click to highlight the chosen Article and then click the "Discard this Article" button. This will move the selected article out of your "current Book contents". You can repeat this for any Article that you do not want in your book.
To Add a discarded Article Back: In the right box, click to highlight the Article you previously discarded and click the "Add Back to Book" button. Don't forget that you will probably want to change its sequence too.