Yup! Once it's connected and everything is installed correctly (This depends on your specific keyboard, I'll just outline what to do in REAPER), open up REAPER and go to Options > Preferences > Midi Devices. Right click on your keyboard and select "Enable." Now add a new track, and give it a VSTi of some sort (ReaSynth works for testing). Click the "R" button to arm the track for recording; a VU meter should show up on the track, and something like "Input 1," or the name of your audio capture device will be on it. Right click the VU meter, go down to MIDI inputs, and select the device you just enabled. "All Channels" or "Channel 1" should work. Now, click the little speaker icon that's on the left of the VU meter to turn on input monitoring. Now, when you play something on your keyboard, you should hear it. You can now record input from it as well. If there's a large delay between pushing a key and hearing something, it's because of the latency settings of your audio device. Use the button in the far upper right to configure this, try setting a lower buffer size.