The mechanical group dealt with the exploding-bridgewire detonators and the explosive lenses. The nuclear group moved to Los Alamos to study the cores and initiators. As part of their training, they attended lectures by Edward Teller, Hans Bethe, Lise Meitner and Enrico Fermi.[38] The electrical and mechanical groups at Sandia, although not the nuclear group, completed their training around the end of October 1946 and spent the next month devising the best methods of assembling a Fat Man, drawing up detailed checklists so that later bomb assembly teams could be trained.