How do I master the basic structure of the Indian Constitution for GS2 for UPSC?

To master the basic structure, focus on the Evolution and Philosophy of the Constitution.
Start with the Preamble to understand its core values, then study the "Basic Structure Doctrine" established by the Kesavananda Bharati case.
Use M. Laxmikanth to link Parts, Schedules, and key Articles (1–51) to their historical origins and modern judicial interpretations.