Welcome to a new reality. Please be patient, depending on the speed of your CPU, this may take a minute or so to load. Once the image appears, you can use your cursor to move around in 3D virtual space. Just click and drag up for forward, down for back, left and right to change direction. To look up and down, you can use the 'a' and 'z' keys on your keyboard.
Have fun.   B.T.W. - you can walk through the walls