it easier than it looks lol, i use this harness for my husky kira in the car.
get hold of the shortest buckles (that fit together) and do them up, then slip the dogs head through, with the padded bit near the floor.
bring the right (dogs right) paw through the hole in the harness, this should leave you able to bring the long bit with the metal ring (and the little x shape where its stitched together) on over the dogs back.
lay the long bit across the dogs back, bring the buckle thats not yet clipped up under the dogs chest and clip it to the corresponding clip.
hope this makes sense.
bassically the padded bit goes along the breast plate and big loop with the metal right hangs off the shoulder blades, you clip the lead to this.
heres a pic, not a good one but you get the idea
btw she does have a check collar and half check on in this pic, ignore them, its nothing to do with the harness