After each salat. You cannot go beyond ten times in a month because prophet Muhammad (S.A.W) said whoever complete recitation of the Qur'an in less than three days did not understand why the Qur'an was revealed. May Allah accept this as an act of ibadat in this ramadan.
The easiest way of completing recitation of the Qur'an in the month of ramadan. Once in a month-4pages after each salat, twice in a month-8pages after each salat, trice in a month-12pages after each salat. It goes that way till ten times in a month which is equivalent to 40pages