How did sher bahadur deuba became the third prime minister​

In 1991, he was elected to the House of Representatives and served as the Minister of Home Affairs in the cabinet led by Girija Prasad Koirala. This cabinet was dissolved, and Deuba rose to become prime minister after Manmohan Adhikari tried to dissolve the parliament again in 1995. During his first term, he signed the Treaty of Mahakali with the Government of India. Deuba's second premiership started in July 2001 following the resignation of Girija Prasad Koirala shortly after the Nepalese royal massacre. His second term saw the rise of Maoists and later he declared a state of emergency, and listed the Communist Party of Nepal (Maoist) as a "terrorist organisation". In October 2002, King Gyanendra dismissed him and his cabinet for being incompetent. The same year, he founded the breakaway party, Nepali Congress (Democratic), after being sacked by the Nepali Congress. He was later appointed as prime minister by King Gyanendra on 4 June 2004, however, he was arrested under corruption charges following the 2005 coup d'état, and he was released on 13 February 2006.

In August 2016, Deuba and Pushpa Kamal Dahal agreed to form a rotational government led by the CPN (Maoist Centre) and the Nepali Congress for nine months each. He was sworn in as prime minister for a fourth stint on 7 June 2017. In October 2017, all ministers from the CPN (Maoist Centre) left the cabinet after they formed an electoral alliance with the CPN (UML) in preparation for the general election and rescinded support to the Deuba government. On 12 July 2021, the Supreme Court ordered the appointment of Deuba as prime minister within 28 hours, the next day, he was appointed by President Bhandari as the prime minister in accordance with Article 76(5) of the Constitution of Nepal.

I hope this helps

just don't strip down in public lol