Here’s a link to an article that describes the process. As long as you can find an area around 50 degrees to store them, they will be fine.
https://www.thespruce.com/how-to-store-canna-bulbs-2132870
Another good source:
http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/visual-guides/digging-and-storing-cannas.aspx