Roland KIYOLA KF-20 and KF-25 do not support Bluetooth headphones or earphones. Use wired headphones or earphones instead.
The KF-20 and KF-25 have two PHONES jacks on the bottom of the unit: one stereo mini plug and one stereo 1/4-inch plug. For details, refer to “Bottom side” section in the KF-20/KF-25 Owner's Manual.