Connect a USB cable to the "USB Out" jack on the rear of the Oxygen 8 keyboard. You do not need to attach a power supply as the USB delivers power to the Oxygen 8 keyboard from the computer.
Connect the other end of that cable to the USB port on your computer. This port is typically located on the side of laptops and on the front of desktops.
Double-click the Reason desktop icon to launch the program. MIDI is a universal interface, so Reason will automatically identify that a MIDI device is connected. But it does not yet know the specific device.
Click "File" and select "Preferences." Click the "Attach Surfaces" tab and select "M-Audio Oxygen 8." This identifies the keyboard as an ancillary control surface, permitting you to perform various commands from the keyboard.
Click "File" and select "Create Mixer." This opens the Reason mixer interface. In here you will see all of the controls and options you would typically associate with a standard recording studio, such as fader dials, mixer channels, mute and solo options and a master mix section.
Right-click on a parameter control in Reason. For example, click on a mixer fader or gain dial to assign that parameter to a dial on the front panel of the Oxygen 8 keyboard. This allows you to control Reason parameters remotely from the Oxygen 8 keyboard.
Select "Edit Remote Override Mapping."
Check the box that says "Learn From Control Surface Input." This means you can select a knob on the Oxygen 8 keyboard simply by moving it, rather than by manually selecting it from the mapping interface in Reason.
Turn the knob to which you want to assign the first command or parameter. This assigns the previously selected parameter to the knob, enabling you to adjust and control Reason parameters from the Oxygen 8. Repeat this process for each of the remaining nine ancillary controls.
Click "Create" and select "MIDI Track." This opens a new channel.
Click "Options" and select an instrument. This sound is then assigned to the channel, which you control from the Oxygen 8 keyboard.