Sorry to hear that you are having trouble connecting the MiniNova to your UR12.
If you are trying to record the internal sounds of the MiniNova you will need to connect a 1/4" cable from the left output of the MiniNova to the 1/4" input of the UR12. Next you would need to set the UR 12 as your audio device in Cubase then create an audio track. Since the MiniNova is connected to the second input of the UR12 you will need to select input 2 for your audio track in Cubase. If you are not able to get signal into Cubase try raising the maximum volume knob of the MiniNova.
Derrick // Novation Technical Support