Complex sentence: Within a few hours of this battle, French soldiers advanced to Marrakech and reached the following morning and found that Al Hiba had runaway from the city to Sous and his left out solders had laid their arms and surrendered.
Split into simpler sentences: Within a few hours of this battle, French soldiers advanced to Marrakech, which they reached the following morning. There they found that al-Hiba had run away from the city to Sous and his abandoned solders had laid down their arms and surrendered.