After the Sons of Liberty disperse, meet up with the Patriot forces. Things will quickly go south and while they hold off the enemy in Lexington, you'll need to head back to Concord to warn your allies.
When you start running, you'll be given a three minute timer. Watch on the right side of the path for a horse and make sure to grab this. It is definitely possible to complete this section on foot and complete the constraints in the three minutes you have but it will be very close. Hop on the horse and start riding.
As you move along the road, be on the lookout for a firing line setting up to kill a civilian by execution. You'll find them as you cross a small town off to your left side. The Red Coats will be across a small bridge and their icon will be a red circle with a white ring around it. Any time you see this icon, it means that they are enemies that are important to kill but are not necessary. Usually, this is used to tell you that they are part of a constraint. Attack these enemies to give the civilian a chance to flee. With them dead, get back on the horse and continue to Concord.
You'll meet up with the leader of the forces in Concord and be charged with directing troops here. Your job is to keep your firing lines steady and tell them when to fire. They won't fire until you tell them to so it's very important for you to pay attention. If you fire too early, you'll miss entirely and if you fire too late, you'll start losing men. When you fire is actually pretty simple when you think about it. The reason your men need you is because they are nervous and inexperienced. The Red Coats are not, however. Wait for the Red Coats to march up and when they stop marching, it's because they've reached the optimal firing distance. You want to shoot sa soon as they stop, before they have a chance to assume a firing posture.
There are three lines of men that you'll have available. You'll start with a group on one side of a bridge. From here, there will be a group on the left and right. Each of these groups will consist of probably 10 or so men taking cover behind rocks or sand bags. When you approach one of these groups, a white circle will form near them. You need to stand in this circle to issue the fire command.
When the battle starts, wait for the first group to come across the bridge. Notice that as they start crossing the bridge but well before the get close enough to fire that they turn into a red "must kill" marker on the map. This will let you keep track of which firing line you need to attend to next. Wait for the Red Coats to stop on the bridge and then issue the fire command. With a single fire command, you should watch the first row of Red Coats go down shortly followed by the second row. If you can eliminate seven groups with a single command each, you will meet a constraint. This shouldn't be too hard as you will have to deal with as many as 16 attack groups.
After you've taken out your first group, make sure that you find each of your groups off to the left and right so you know exactly where they are. These two groups need to shoot at soldiers across the water standing on the shore. It may seem like a rather long distance compared to the soldiers on the bridge but as long as the enemy has stopped moving, you should have no trouble hitting them.
As the battle approaches the end, you'll start coming up against more and more frequent groups so you'll almost certainly want to issue a command and start riding for the next line immediately so you can have all three lines firing almost as quickly as they can load.
When you've toppled 130 enemies total, you will have to return to James Barrett. Doing so will complete the memory.
