eight o'clock
They were the 12th , 20th , 23rd , 25th , 37th and 51st . Some regiments of Hanoverians were in line behind them . The British cavalry were on the duke 's right . The morning was misty , and it was not until eight o'clock that both sides were ready , and indeed even then Contades ' infantry was not finally settled in its position . The battle began with an attack by some Hessian regiments on the village of Hahlen , and by a very heavy fire of artillery on both sides . The orders to the English regiments had been , `` March to attack the enemy on sound of drum , '' meaning that they were to move when the drums gave the signal for the advance . The English , however , understood the order to be , `` You are to advance to the sound of your drums . ''