Answer:
The Confederates formed a defensive line on the house
Step-by-step explanation:
This happened during the First Battle of Bull Run. At that time, Brig. Gen Thomas Jackson of Virginia ordered his soldiers to take over Henry's house and form a formation there. (Henry was a Navy surgeon for the Union at that time)
After forming the defensive line, Jackson ordered his sharpshooters to start firing toward the Union Soldiers. Because of this, the Union Soldiers were forced to retaliate by opening fire to Henry's house.