Dig them up with out injuring the roots, dust off excess soil, rinse with water, air dry at room temp, put them in a container and store them indoors until you are ready to plant again, try and store them at room temp.
If it is not too cold where you live, you can leave canna bulbs in the ground. If it is too cold for the plants, you will need to take up the rhizomes and store them. Trim the lily stalks to one inch. Take up the bulbs carefully with a trowel and store between layers of newspaper in a bucket.
Take an old pair of panty hose put the bulb all the way to the toe and tie a knot in it above the bulb and continue in this manner till the panty hose are full then hang them up somewhere and you are done.