Short answers, pulled from the story.
The UN officially came into existence on the 24th of October 1945 upon ratification of the Charter. The Security Council held its first session on the 17th of January 1946 at Church House in London.
Five permanent members hold veto power over any substantive resolution: China, France, Russia, the United Kingdom, and the United States. These were the great powers victorious in World War II or their recognized successor states.
Since inception, 269 vetoes have been cast according to available records. The Soviet Union or Russia used this power 128 times while the United States employed it 89 times.
As of the 28th of February 2023, there were 86,903 uniformed and civilian personnel serving across twelve missions with contributions from 121 countries. The largest mission was MONUSCO in Democratic Republic of Congo including 20,688 uniformed personnel.
Top contributors included the US at 27.89 percent followed by China at 15.21 percent and Japan at 8.56 percent. In fiscal year 2021-2022 expenditures reached $6.38 billion covering ten ongoing missions plus liquidation of Darfur operation.