The note browser supports a few gestures for selecting notes, whether in stacked or spread mode. When a note is selected, it begins to jiggle. You can select multiple notes for reordering, moving to another stack, or deleting.

The supported gestures are…

GestureEffect
Long tap (tap and hold down) on a noteSelect the note
Drag selected notesBegin reordering notes
Tap another note when notes are already selectedAdd note to the selection
Tap backgroundDeselect notes