if you are living somewhere where you cannot leave the dahlia tubers in the ground over winter, then some of these ideas might be of use. find one that works for you- tweak it to fit your needs.
One method that is used- and I have tried it with great success, was to wrap or lay the tubers in paper.
Some just lay the tubers out in trays lined with clean newspaper. Others wrap each tuber loosely in a sheet of newspaper before laying them out in trays; wooden ones are ideal, or even shallow cardboard boxes. They must then be stored in a dry, frost-free place with good air circulation
Pack the tubers in a box or pot and cover them with dry compost to help prevent them from dehydrating.
Store the tubers in a storage bin, chilly bin, basket, paper bag, or cardboard box filled with sand, sawdust, peat moss, or vermiculite.
I personally store mine in banana boxes as soon as they're uplifted and dry - I don't remove the dirt from them-. the boxes are open-topped and the dahlias are stacked in them and the whole lot then stays in my garage until spring. I regularly open the garage to air them out and prevent mold