Stacks can be reordered, or moved inside groups.

To reorder the stacks and groups in a list, tap the Edit button at the top-right, and then drag the grip on the right side of the stack’s row to move it up or down.

To move a stack inside a group, tap the Edit button, and then tap on the stack. In the stack editing screen, tap the Location row, and finally choose the group you want to move the stack into.