Short answers, pulled from the story.
The Battle of Guam took place from the 8th to the 10th of December 1941. Japanese forces landed at Dungcas Beach north of Agana in the early morning of the 10th, and Captain George McMillin officially surrendered at 06:00 that morning.
The American garrison consisted of 271 naval personnel and four nurses, 145 Marines at Sumay, 246 members of the Insular Force Guard, and 80 Guam Insular Patrol police officers. The defenders were equipped with 170 M1903 Springfield rifles, 13 Lewis guns, and 15 Browning Automatic Rifles, with no artillery on land.
The 1922 Washington Naval Conference required both the United States and Japan to refrain from further fortifying their western Pacific island possessions. Guam's coastal artillery was removed by 1930, and a 1938 U.S. Navy proposal to build new fortifications was rejected. By 1941 the island held a "Category F" defense rating, which ruled out new construction.
The South Seas Detachment under Major General Tomitaro Horii numbered approximately 5,500 men and was drawn primarily from the 144th Infantry Regiment and units detached from the 55th Division. An additional 370-man naval landing company based at Saipan also took part. Japanese intelligence errors led the attackers to commit disproportionately large forces to the operation.
George Ray Tweed was a Radioman First Class who was one of six U.S. Navy seamen to evade capture after the fall of Guam. Chamorro residents moved him from village to village for two years and seven months, protecting him at great personal risk. The Japanese beheaded Chamorro suspects in reprisal, but Tweed survived until he was rescued prior to the Second Battle of Guam in 1944.
U.S. Marine losses totaled 13 killed and 37 wounded across the aerial bombardment and the landing. Eight U.S. Navy personnel were killed, and four Insular Force Guard members died with 22 wounded. Thirteen American civilians were also killed. Japanese losses were one soldier killed and six wounded.