Clean the seats really well - brush and vacuum. Then apply about 4 oz of RO to each seat. I prefer to apply it with my hands, but some people use a brush. Also some people spray the RO on the seats, but I don't like to spray RO because I don't want to get RO on anything but leather.
After you get the leather covered with RO, just let it sit and absorb. If it's sunny, park the car in the sun with the windows up so that the interior gets hot. The heat helps the RO soak in. Let the RO stay on the leather all day, or longer if you have time.
After the RO has absorbed or you just can't wait any longer, get out the Pristine Clean (PC). I suggest a spray bottle for this. Just wet it down good with PC and wipe it off with a good MF or cotton towel. The seats will be a little damp, but will dry quickly.