 With a battle plan in order , Lee sent a draft to his lieutenants , written by his chief of staff , Col. Robert Chilton ( see right box ) . The orders were not well @-@ crafted , however , since they designated the yell of a single charging brigade as the only signal of attack for a full fifteen brigades . Amid the tumult and clamor of battle , this was bound to create confusion . Moreover , Chilton 's draft effectively left the attack solely at the discretion of Lewis Armistead , who had never before held command of a brigade during battle . The draft also did not note the time that it had been written , which later caused confusion for Magruder . 
