Within the editing page, click 'Edit Quotes' on the left.
To edit a quote, click the 'Edit' button next to the quote. To delete a quote, click the red 'X' that's next to the quote in the list. To sort quotes, use the arrows under 'Sort' to click and drag them up or down to where you want them in the list.
Make sure to save your changes by clicking on the green 'Save' button at the top right and bottom of the page.