Short answers, pulled from the story.
The First Battle of Bull Run was fought on the 21st of July 1861 in Prince William County, Virginia, just north of what is now the city of Manassas and about thirty miles west-southwest of Washington, D.C.
The Confederacy won the First Battle of Bull Run. Confederate forces under Brig. Gen. P. G. T. Beauregard, reinforced by troops from Brig. Gen. Joseph E. Johnston's Army of the Shenandoah, drove the Union army into a disorganized retreat toward Washington, D.C.
Brig. Gen. Thomas J. Jackson earned the nickname "Stonewall" during the First Battle of Bull Run when his Virginia Brigade held firm on Henry House Hill. Brig. Gen. Barnard Bee reportedly rallied his own retreating troops by shouting, "There is Jackson standing like a stone wall." Bee was mortally wounded shortly after and died the following day, leaving the exact intent of his words unclear.
Rose O'Neal Greenhow was a Washington socialite who led a Confederate spy network set up by former U.S. Army captain Thomas Jordan. On the 9th and the 16th of July 1861, she passed secret messages to Confederate General Beauregard revealing Union military movements and McDowell's plans. Confederate President Jefferson Davis later credited Greenhow personally with ensuring the Confederate victory.
Union casualties were 460 killed, 1,124 wounded, and 1,312 missing or captured. Confederate casualties were 387 killed, 1,582 wounded, and 13 missing. Bull Run was the largest and bloodiest battle in United States history up to that point.
Battlefield confusion during the First Battle of Bull Run arose from the similarity between the Confederate "Stars and Bars" and the Union "Stars and Stripes" when the flags were furled or fluttering. This confusion led Confederate commanders to adopt a new, distinctive Confederate Battle Flag to prevent friendly-fire incidents, and that flag eventually became the most recognized symbol of the Confederacy.