To put a "swing" delivery into your music, instead of using (say) two eigth notes, use a quarter note followed by an eight note, then highlight them together and click on the "triplet" button (Ctrl-T).
See Also: https://forum.noteworthycomposer.com/?topic=2363, https://forum.noteworthycomposer.com/?topic=2288, https://forum.noteworthycomposer.com/?topic=2289