OK, I finally found the answer, no thanks to anyone here. I'll post it in hopes of helping someone else. Under your store, click on Categories. Choose a Category and then click Products. When the whole list comes up (All), click on Assigned. This will give you just the products in that Category. Then you can order them manually, or by the Name or Product Number sort. These changes WILL show up in the store itself, not just in your list of items.