Install the drivers needed for your computer to recognize your keyboard through its USB port. If using a MIDI-to-USB interface, install the software included with your unit. If you are using a USB-ready keyboard, install the software that came with your keyboard.
Run Cubase on your computer. Locate the "Devices" menu on the taskbar and choose "Device Setup."
Locate the MIDI folder. Select "All MIDI Inputs." If your drivers were installed correctly and your keyboard is connected via USB, you will see it listed under "All MIDI Inputs."
Select "Default MIDI Ports" from the MIDI folder. Select your MIDI device from the list of available devices and click "Apply."
Select "Direct Music" in the MIDI folder. Locate your MIDI device on the list and highlight the "Show" option so it will be displayed on the pop-up menu while using the program. Click "Apply." Your MIDI device is now set up and ready for use with Steinberg's Cubase.