Try to get unfinished wooden boxes for storage. Ideally something that doesn't have a strong residual odor. But a few days in a large sealed bag with a cup of baking soda next to the box can remove odors.
Boxes aren't the only option. I've also seen various plastic baskets used for singles storage.
Cedar pieces or sheets can be attached to the lid of the coolidor with double stick tape. I used 3M molding tape since it was in the shop. As already stated the cedar isn't a necessity, but I got some sheets and blocks for free.
The blocks are set that way on the lid because there was a small gap where the lid hinges. Nothing that I worry about but the blocks do seem to help humidity stability.
The white racks are cupboard organizers. The large one covers the entire bottom with more cedar sheets and a few blocks below it.
Don't mind the sponge thing as this is an old pic from when I first put the coolidor together.
(click to enlarge)