To move a note, you must first select one or more notes to move. To select a note, long press on a note thumbnail. To select multiple notes, tap other note thumbnails after a single note has been selected. After selecting the desired note(s) to move, tap the move icon in the action bar at the top (looks like a notebook with an arrow in it), then choose the desired notebook from the list.
To move a note, long press on the note thumbnail and choose Move from the context menu, then choose the notebook you would like to move the note to.
If you only have one notebook and you want to move a note out of that notebook, long press on the note thumbnail and choose Remove from notebook.