So after step one, we now have this picture as shown in this diagram. So these two strands have now separated. Now once we separate the two strands, we begin decreasing the temperature of that solution. So we cool the solution to about 54 degrees Celsius. And the reason we cool it to that specific temperature is because at that temperature, that is when those DNA primers will begin to bind onto the flanking sequence. Now, because we're going to have so many DNA primers moving about between this region that will keep these two single strands of DNA from forming those bonds and reforming that double stranded helix formation.