Each new selection is added to the bottom of your list when you click on any DVDs button.
To reorganize your selections, change the ranking on the left and click the "Update" button found above (ex. by changing 3 to 1, the third selection is now number 1 and the rest will reorganize themselves accordingly.)
To remove a selection, check the box(s) on the far left under the "Remove" column and click the "Update" button.