Short answers, pulled from the story.
The privy chamber was the private apartment of a royal residence in England, housing the king's bedroom, library, study, and lavatory. It was staffed by the Gentlemen of the Privy Chamber, noble-born servants who attended the king in private, with the Grooms of the Privy Chamber ranked below them.
The privy chamber's institution is credited to King Henry VII, who reigned from 1485 to 1509. It became more formally organized once his son, Henry VIII, took the throne, with a regular staff of gentlemen, ushers, grooms, and pages.
The Groom of the Stool was a male servant responsible for the king's royal excretion, cleaning the monarch's body after he used the toilet. The role carried high honour and standing rather than shame, and grew especially influential as Henry VIII aged and needed more physical assistance.
In Edward VI's reign, a gentleman of the privy chamber earned £50 a year, a gentleman usher earned £30, and a groom earned £20. These men belonged to what was called the Ordinary of the King's Honorable House.
By Queen Mary's death, her privy chamber establishment included seven Ladies and thirteen Gentlewomen alongside only about half a dozen Gentlemen and Grooms. Under Elizabeth I, the number of men in the household fell to just two, one Gentleman and one Groom.
James VI became king of England in 1603 and turned his Scottish chalmer varlets into grooms of the bedchamber. The new Privy Chamber formed in May 1603 had 48 gentlemen, with twelve in service at any one time, and some English courtiers such as John Fortescue lost their posts for resisting the Scottish appointees.