Controls

"Swap" button/"S" key

Swaps the two selected items then moves the cursor one space to the right.

"Next" button/"N" key

Leaves the selected items in their current order then moves the cursor one space to the right.

When you reach the end of a pass press "OK" or the "Space" key on your keyboard if you believe the list is sorted, otherwise press "Cancel" or the "Escape" key on your keyboard to perform another pass.

If you manually change the number of elements you will need to restart to generate a new list of that size.