What is the methodology of the Pious Predecessors (Salaf Sālih), and what are the books that aid in following it from beginning to end? Is it considered one of the sects?

The Salaf are the Companions (Sahabah), the Successors (Tabi'un), and their successors who followed them in righteousness. Their methodology is the Quran and the Sunnah. This methodology is not restricted to a specific group but includes everyone who believes in their creed and acts according to their methodology. Among the books on their creed are "Al-Aqeedah Al-Wasitiyyah" and "Sharh Al-Tahawiyyah." As for jurisprudence (Fiqh), the People of the Sunnah have four recognized schools of thought: the Hanafi, Maliki, Shafi'i, and Hanbali. It is incumbent upon the student of knowledge to avoid blameworthy fanaticism.