Order Manually

Open a List

Switch to "Prepare" mode

Choose "Select a Store" (!), go back to List tab

Press "Arrange", choose "Order Manually"

Now each item has a hash tag Ordering Control on the right

Grab the Control and drag the item

If you choose a Specific store (Custom store), you'll see "Like manually ordered" option only (to avoid confusion of different orders for the same items).

Suggestion:

In order to arrange items at a Specified store please use "As Checked-Off" sort option.

This sort lets you arrange items in the order in which items are checked-off. It moves checked items to the bottom of the list, and it shows unchecked items in the order they have been checked during previous shopping trips with this list.