A: By being mindful of characteristics of realities that appear.  The instant there is sati mindful of characteristics of realities of one kind or another, samma-sankappa (right thought) would think or concentrate on the characteristics of arammana which is appearing and panna begins to study and examine the true characteristics of realities that appear little by little until the knowledge grows.

Knowledge would ensue and develop from the examination of and learning about the characteristics of realities when sati is mindful of the realities.  Realities arise, appear and then fall away so rapidly.  Sometimes one does not have the time to study the characteristics such as when one hears, sati can only be mindful of the hearing very slightly.  One does not have time to examine and study to know that it is the reality that knows sound, the hearing is already gone.  Even though in the beginning the panna does not arise to clearly realize the characteristics of hearing, this is normal.  No one can hold sound or run test on the nama-dhamma, inspect and study it, but hearing will arise again.  Those who develop sati and panna would be able to be mindful of the characteristics of the nama-dhamma that hears the next time.

Right now sati can arise to be mindful of the characteristics of nama-dhamma or rupa-dhamma appearing through the eye, ear, nose, tongue, bodysense or mind, one way or the other, one characteristic at a time.  And examine and study to know the characteristics of the specific reality little by little until panna could accumulate and clearly know the differences between nama-dhamma and rupa-dhamma and is able to differentiate the distinct characteristics of the nama-dhamma that hears, from sound, etc.  Finally one would be more accustomed to the characteristics of the nama-dhamma and rupa-dhamma.  Once that happens, the knowledge of the characteristics of nama-dhamma and rupa-dhamma would increase even more.  No matter which nama-dhamma or rupa-dhamma would arise at what location, sati and panna would be able to arise and be mindful of their specific characteristics, in that instant, normally, as they really are.  To develop sati-patthana is to develop sati and panna.  Whichever knowledge is developed to arise that knowledge would accumulate and attenuate ignorance at the same time.