If you're just looking for getting vision on your dashboard with a USB camera, I stripped down the SimpleVision template to 3 lines of code that you run when initializing everything:
Code:
CameraServer camera = new CameraServer();
camera.setQuality(50);
camera.startAutomaticCapture("cam0");
When you start up the driver station while connected to a RoboRIO running this code, go to the FRC PC Dashboard. In the bottom left of the "drive" pane, there should be a dropdown menu with the options of no camera, SW camera, HW camera, and IP camera. I believe you set this to SW camera (If that doesn't work, try HW camera. It's one of the two. I honestly cant remember, even though I was using it literally 2 hours ago). This should give you a live camera feed in what was formerly a big empty space of the dashboard. One thing I did notice tonight about that string "cam0"; this does not name the camera, it determines what camera to get the feed from. I believe the first camera you connect is automatically addressed as "cam0". I could be wrong on this, I haven't tested using multiple cameras. I learned this the hard way by replacing "cam0" with "PotatoCam", then not understanding why I couldn't get any feed whatsoever.
Good luck!