You need some more Parts which you can find here:
Split Up Spirit Island Trays von KarnEdge | Kostenloses STL-Modell herunterladen | Printables.com
or here:
Spirit Island - Easy Setup All In One Organizer by trita - Thingiverse
The author remixed this model.
I have adjusted the partsthat they can be printed without supports. Also I have rounded the edges for smoother surfaces.