What is the procedure for prosecution under sections 352 and 351(2) of the BNS?

Sections 352 (intentional insult to provoke breach of peace) and 351(2) (criminal intimidation) of the Bharatiya Nyaya Sanhita are treated as non-cognizable and bailable under the BNS, so police cannot independently arrest or start an investigation without a Magistrate's order; you should (1) lodge a written complaint at the local police station and obtain the station diary/NCR entry, (2) if police refuse effective action ask the SHO to refer the matter to the Magistrate or file a private complaint before the Judicial Magistrate asking the Magistrate to take cognizance or direct investigation, and (3) if police still do not act invoke the Madhu Bala and Lalita Kumari lines of authority to request magistrate-ordered investigation or approach the High Court or supervisory authorities (SP/State Police Complaints Authority) for mandamus; these steps are supported by BNSS provisions requiring police to record non-cognizable information and to refer the informant to a Magistrate [BNSS s.174/175: https://indiankanoon.org/doc/91117739/], and by the BNS provisions creating offences under s.351 and s.352 [BNS s.351: https://section1.in/bharatiya-nyaya-sanhita-2023/; BNS s.352: https://www.latestlaws.com/bare-acts/central-acts-rules/bns-section-352-intentional-insult-with-intent-to-provoke-breach-of-peace/]. The Supreme Court and higher'court precedents make clear a magistrate can order police investigation and that police must not 'burke-complaints (Madhu Bala v. Suresh Kumar, see https://indiankanoon.org/doc/740262/; Lalita Kumari v. Govt. of U.P., see https://indiankanoon.org/doc/61439929/). In practice the remedy works but is often slow and requires persistent follow up; in Maharashtra you can also complain to the State Police Complaints Authority or move the High Court if there is inaction (Maharashtra SPCA directives on FIR/registration noted in local orders and press reports: https://timesofindia.indiatimes.com/city/mumbai/fir-now-must-if-plaint-clearly-discloses-cognizable-offence/articleshow/121698383.cms). Evidence and trial procedures will follow the Bharatiya Sakshya Adhiniyam rules on proof and witness examination [BSA overview: https://courtbook.in/search/act/the-bharatiya-sakshya-adhiniyam-2023-6690db0827e75d8a5ebb2db5]. Bottom line: it is usually worthwhile to pursue the magistrate route because the law gives statutory and judicial remedies, but expect delays and consider cost, alternative dispute resolution, or civil remedies depending on your objectives.