Not sure if yours came with a manual so, this is from the manual of the DAB +
Pairing your Bluetooth® device for the first time
► Press the Source button [j] to select the Bluetooth® mode.
The Bluetooth® status icon flashes to show the SysRock is discoverable.
► Activate Bluetooth® on your mobile device according to the device's user manual to link up to the SysRock.
► Locate the Bluetooth® device list and select . Some mobile devices (which are equipped with Bluetooth® interfaces older than the BT2.1 standard.), require entering the pass code “0000”.
Once the connection is established, the Bluetooth® icon will cease flashing and display a check mark next
Deleting Bluetooth® device pairings
► To delete all Bluetooth® device pairings, press and hold the Preset 4 button [g] until shows on the display. The SysRock will turn off automatically after the memory is cleared.