How do I sort the list myself and undo a wrong order?

Two ways: press and hold an item in the open list and drag it to the right spot. Or — clearer when you're reordering several — open „⋯“ at the top right → „Sort items manually“; drag handles then appear.

Important: a manual move isn't a one-off — it's a head start for Smart Sorting. pon remembers your placement as a strong signal and keeps the position exactly that way, releasing it only after a few of your own shopping trips; after that, your move still counts as a weighty vote in the learned order.

Especially at the start, when pon doesn't yet know your path through the store, a quick manual sort gets the list into shape fast — without giving up Smart Sorting at all.