Short answers, pulled from the story.
The Russell-Einstein Manifesto was issued in London on the 9th of July 1955 at a press conference held at Caxton Hall. Bertrand Russell presented it during the Cold War to draw attention to the dangers of nuclear weapons.
Eleven intellectuals and scientists signed the manifesto, including Bertrand Russell, Albert Einstein, and Joseph Rotblat. With the exception of Leopold Infeld, all signatories were Nobel Laureates, though Rotblat had not yet received that honour when he signed.
Yes. Einstein signed the manifesto shortly before his death on the 18th of April 1955, more than two months before its public release in July of that year.
The manifesto called for a conference where scientists would assess the dangers that weapons of mass destruction posed to humanity's survival. It emphasised political neutrality and extended the question of nuclear danger to all people and governments, not only those in power.
The manifesto explicitly called for an international scientific conference. After plans for India fell through due to the Suez Crisis, and an offer from Aristotle Onassis to host in Monaco was declined, Canadian industrialist Cyrus Eaton offered to finance the meeting in Pugwash, Nova Scotia. The first Pugwash Conference on Science and World Affairs was held there in July 1957, with the manifesto serving as the conference series' founding charter.
The most frequently cited line from the manifesto is "Remember your humanity, and forget the rest." Joseph Rotblat quoted this phrase when he accepted the Nobel Peace Prize in 1995.