Short answers, pulled from the story.
The Watergate scandal began on the 17th of June 1972 when five burglars broke into the Democratic National Committee headquarters at the Watergate complex in Washington, D.C. These intruders planted listening devices disguised as smoke detectors and removed doors from their hinges to enter the office before security guard Frank Wills discovered the operation around 1:50 a.m.
G. Gordon Liddy became general counsel for the Committee for the Re-Election of the President and proposed Operation Gemstone while E. Howard Hunt was identified by federal prosecutors during the investigation. President Richard Nixon approved a plan to have the CIA pressure the FBI to drop its probe under the pretense of national security which later became known as the Smoking Gun tape.
On October 20, President Nixon ordered Attorney General Elliot Richardson to fire Special Prosecutor Archibald Cox but Richardson refused and resigned in protest. Deputy Attorney General William Ruckelshaus declined the order and was fired after offering his resignation before Solicitor General Robert Bork agreed to fire Cox.
On the 27th of July 1974 the House Judiciary Committee voted 27-to-11 to recommend obstruction of justice as grounds for impeachment. They also recommended abuse of power and obstruction of Congress following an expert panel conclusion that an 18-minute gap on a tape had been erased using hand keys rather than a pedal.
President Richard Nixon announced his resignation effective at noon on the 9th of August 1974 after three Republican leaders informed him he lacked enough support for acquittal on August 7. Vice President Gerald Ford succeeded him declaring our long national nightmare is over and issued Nixon a full pardon for all acts committed as president on the 8th of September 1974.