You must have more than just a commander with you. Slot eight captains with three lieutenants each to be safe. Select the Beginner difficulty setting. If possible, use a horse that has a Piercing passive, such as Lu Bu's default horse, Red Hare. Try to have your attack high enough to one hit kill from your horse with your basic attack. Go to the Jiangdong region and fight in Guangling (18% region subjugation required). One possible setup will give you will have a noticeable advantage with over 50% subjugation while the enemy only appears from the right side of the map. If you do not end up with this scenario, exit the battle and try again. All of the enemies will be grouped at a single location, giving you an easy opportunity to ride up and down the small area they appear from and kill anyone that is a Mobile Unit Captain, Unit Commander, or named officer. Once clearing them out, go to the enemy bases and capture them to remove the possibility that they will get reinforcements. Next, break through their defensive line and eliminate the commander.
Complete the indicated task to unlock the corresponding stage.
Complete the following tasks to unlock PlayStation 4 trophy rewards.