This image is set for "Cross-eyed" viewing. Position yourself so you are looking straight at the center of your screen, focus on the border between the images, and then slowly let your eyes cross until the two images fuse into a single 3D image.
Or you can select other viewing methods from the pull-down menu at upper left.
If you happen to have a pair of red/blue glasses from some other 3D application, the "Red/Cyan" setting works quite well.