Short answers, pulled from the story.
The Overland Campaign began on the 4th of May 1864 when Union forces crossed the Rapidan River. Lt. Gen. Ulysses S. Grant directed the Army of the Potomac against Confederate Gen. Robert E. Lee's Army of Northern Virginia.
Lee forced an engagement within dense scrub brush known as the Wilderness on the 5th of May 1864 where fighting continued until nightfall with neither side gaining advantage. A field caught fire during hand-to-hand combat causing men from both sides to burn to death while wounded comrades perished nearby.
Maj. Gen. John Sedgwick died instantly on the 9th of May 1864 when a sharpshooter shot him through the head while he inspected his VI Corps line. Horatio G. Wright replaced him immediately after the incident.
Forces met at noon on the 11th of May 1864 at Yellow Tavern which is an abandoned inn north of Richmond. Confederate cavalry leader J.E.B. Stuart was shot while shouting encouragement and died in Richmond the following day.
Grant planned to leave North Anna in another wide swing around Lee's flank marching east of the Pamunkey River to avoid direct confrontation with fortifications. Supply depots moved to Port Royal then White House on Pamunkey before final positioning.