Commander

Form Ranks!
The Commander is a highly trained military leader trusted by the King to protect the town from threats. He oversees all  soldiers  and is responsible for external security and military actions. In the event of a attack or siege on the town, the Commander is expected to be the one to lead the soldiers and town guard to fend off the aggressors.

In the town's hierachy, the Commander is technically third in authority of the town. They are subordinate to the Baron and the Steward but outrank the Steward during external threats. Their main responsibility is overseeing the town's military forces and, during external threats, the town guard.

Your Duties
As stated above, external security is your responsibility. Sending a few soldiers on patrol outside the town is a good way to preserve the peace and would deter enemies from striking if they knew you are always looking out for them. Telling them to stay in groups is a good idea, as a lone soldier can get ambushed and taken down easily while attacking two or three is much harder.

In the event of an invasion. You should get all civilians into a secure building, such as the keep. This lets your men fight without worrying about stray civilians. Remember, the Baron's safety is of the highest importance in the town. Protect him at all costs, but of course protect the civilians as well, as it is your job.