The JU-06 has a mono signal, but its chorus is stereo.
So record any one voice sound (bass, leads, etc.) in mono, while any sound with chorus (pads, strings, etc.) will be recorded in stereo.
As simple as that!
PS: don't forget about the recording level, use an external preamp and make sure the average recording level is around -18 dBs (0 dB VU) for optimum results. You could also record via the USB interface but note that the incoming signal will be a little lower, so it's best to use an external preamp audio interface.