The "Up Next" List shows you the current playing song and the queue of waiting song. Editing this list a very easy task. To reorder the list just drag a row and move it to the supposed position. To delete an entry from the list, just swipe the row and the entry will be removed There is also a a button to clear the list with one tap. You can also switch the view to a nice cover art view, to do so just tap the button on the titlebar.
To add new Songs to the List just swipe a row to get the context menu showing you some options. Here you can simply add a Song, an Album, an Artist and even a Genre to your "Up Next" List. You can also add a shuffled list of an Album, an Artist or a Genre to your List. The last option its to add this Song, Album or Artist to your favorites list. This works in every list.