Short answers, pulled from the story.
Frank Baker, Shepard Mallory and James Townsend crossed Hampton Roads harbor at night on the 24th of May 1861 to seek refuge inside Fort Monroe in Virginia. These three enslaved laborers had previously been forced to build an artillery battery at Sewell's Point aimed directly at the fort.
Major General Benjamin Butler refused to return the men under the federal Fugitive Slave Act of 1850 after Virginia declared its secession from the United States on the 24th of May 1861. Acting Master William Budd used the term for the first time in an official US military record on the 10th of August 1861.
By April 1865 less than four years after the initial decision, an estimated 10,000 people escaped slavery to gain contraband status. More than one hundred contraband camps operated across the South by the end of the war.
Navy Secretary Gideon Welles issued a directive regarding persons of color commonly known as contrabands on the 25th of September 1861 that authorized pay at the rate of $10 per month plus a full day's ration for these workers. Three weeks later the Union Army began paying male contrabands at Fort Monroe $8 a month and females $4.
For most contrabands full emancipation did not occur until the 6th of December 1865 when the Thirteenth Amendment ratified abolition except as punishment for crime. Mary S. Peake began teaching both adult and child contrabands to read and write within the Grand Contraband Camp before this date.