What was the unions goal when the battle of bull run began

The goal of the union was to CAPTURE the CONFEDERATES who has left the Union

Explanation:

The battle of the Bull Run also knows as the Manassa was categorized as the first major civil war. This war was fought in July 1861 between the Unions and the Confederate

However, the Bull Run battle was a result of some members of the south who left the union due to slavery  to form  the confederate. Brigadier General Irvin McDowell leads the army of the union while Brigadier General P.G.T. Beauregard leads the confederate. There were several casualties who we killed during the war. The tactics of the confederate gives them the edge over the Unions of armies to win the war.