Exporting created style in PSR SX900

[Makoye]

Hi, I am the beginner at using PSR SX900. My interest is to compose musical beats which inputs respective notes of the melody and harmony notes in four part harmony. The song should have intros and recognized pattern such as Verse-Chorus-Bridge-Chorus. I don't know how to put it in MIDI recording. I kept trying doing it in the style creator via intros, main variations to compose a four part harmony. However, I don't know how to assemble these parts into a compelete song and export the in MIDI file and/or audio file for external music performance. Thanks in advance.