Chapter 3 of 'Al-Muneer fi Ahkam at-Tajweed' discusses the concept of 'makhraj', which refers to the points of articulation for letters in Arabic pronunciation. It outlines five general regions of articulation: the oral cavity, throat, tongue, lips, and nasal cavity, detailing their specific points and the letters associated with them. The chapter also highlights differing scholarly opinions on the total number of articulation points.