Click on the sidewalk to move forward along the bridge walkway.  To see the surrounding area, click the right side of the picture, and then click the left of the picture to face forward again. 
If you see an icon on the picture that looks like this:

arrow.gif (2100 bytes)

Click on it to look in the direction it points.

To face forward again after looking up, simply click on the bottom of the picture.  To face forward after looking to the left, click the right side of the picture.  To face forward after looking down, click the top of the picture.

At either end of the walk, you will see an arrow in a blue circle that looks like this:

arrow for cable.gif (1272 bytes)

Click on it to walk the bridge cable.

The green arrow rules apply to the cable walk as well.  Have fun!