They go in order. The ones at the very bottom are the graphic novels and the Legends.
1: The Dragonet Prophecy
2: The Lost Heir
3: The Hidden Kingdom
4: The Dark Secret
5: The Brightest Night
6: Moon Rising
7: Winter turning
8: Escaping Peril
9: Talons of Power
10: Darkness of Dragons
11: The Lost Continent
12: The Hive Queen
Bottom:
Left: The Dragonet Prophecy: The Graphic Novel
Middle: The Lost Heir: The Graphic Novel
Right: Darkstalker: Legends