One side is easy. You load one pad with a bit of solder, try to stay closer to the edge where you can put the iron on when you place the cap down. Place the cap down and heat the pad; Solder will melt and the cap is held down on one side. Second side. The contact are not totally hidden unde the cap, the stick out a bit. Heat the pad and the bit of contact with your iron and apply the solder, it will all come together.
Maybe I can make a video if I can find a board that I haven't populated.