Since the beginning of warfare, soldiers have had to know how to work together to form a cohesive battle-line. Professional soldiers train with their fellow soldiers until their job becomes a craft, maybe even an art. Coordinating their movement, they can hold the line against much more powerful foes.

Level 3: Martial Discipline

You gain Martial Discipline points equal to your Proficiency Score plus your Wisdom Modifier.

Martial Discipline points are spent to use your subclass abilities.

You regain half of your Martial Discipline on a short rest and all of them on a long rest.

Level 3: Defensive Drills

Beginning when you choose this archetype at 3rd level, you gain several defensive drill techniques from long hours of practice shoulder to shoulder with your allies.

While an ally is within 5 feet, attacks against you or said allies cannot gain Advantage. In addition, you can spend a point of Martial Discipline to use one of your Defensive Drills:
Closed Ranks: Spend your reaction and a point of Martial Discipline prevent a Critical Hit on an attack against an ally.
Flexible Formation: Spend Martial Discipline and a bonus action or, when an ally within 5 feet  is attacked by a melee attack, your reaction, to swap positions with, or walk through a willing ally.
Formation Resources: While you make an attack with a thrown weapon, and have at least one ally within 5 feet, spend Martial Discipline to add 2 to your hit roll per ally within 5 feet, and add a 1d4 to your damage roll per point of your Wisdom Modifier.

In addition, setting up and picking up camp takes half as long as it would for most others, and you can light a fire in wet conditions others would not be able to.

Level 7: Close Quarters Adept

Your many battles shoulder to shoulder with your allies has provided you with additional abilities to maneuver along with your allies. Starting at 7th level, If you have an ally within 5 feet, you have advantage in saving throws against abilities that would displace you against your will. In addition you gain Close Quarters Procedures:

Confined Space Combat: When you attack an enemy within 5 feet who is within 5 feet of an ally who is within 5 feet of you, you can spend a Martial Discipline point to either gain Advantage, or, spend two and, should the attack succeed, consider it a Critical Hit.

Interlocking shields: If you're holding a shield or a pole weapon in your hands, and you have an ally within 5 feet, you can spend a Martial Discipline point to impart disadvantage on an enemy attacks against you or an ally within 5 feet. This does not require a reaction.

In addition, you have advantage on constitution checks and saving throws that relate to marching long distances.

Level 10: Squad Leader

Organizing your battle formation through many battles, you've learned how to coordinate your allies effectively. Starting at 10th level, you can spend Martial Discipline and half of your movement to move any willing allies within 5 feet, and those 5 feet from those, in the same direction you are moving.

In addition, second with restores half of your spent Martial Discipline, and Formation Resources uses a D6.

Level 15: Close Quarter Master

Few have mastered the art of Battle Formations quite like you. Action surge adds temporary Martial Discipline points until the end of combat equal to your Wisdom Modifier. Formation Resources now uses a d8. You also gain Formation Mastery abilities:

Masterful Formation: At the start of your turn, you can spend a Martial Discipline point to Shuffle around or push 5 feet any willing allies within 5 feet of you, or within 5 feet of those.

Coordinated Strike: Spend 3 Martial Discipline points to allow allies who can hear you or see you to use their reaction to perform a melee or ranged attack against a designated enemy.

In addition, any time you add your Constitution Modifier to something, add your Wisdom Modifier too. This includes health points.

Level 18: Defensive Formation

Your battle formation becomes unbreakable, even against powerful spells. Any ally you can hear or see within 5 feet of any another ally count towards your ally within 5 feet of you requirements. In addition, you gain Defensive Formation:

Defensive Formation: Any time an ally you can see or hear that is within 5 feet of another ally fails a saving throw, you can spend a Martial Discipline point to let any ally within 5 feet of that ally to use their reaction to let them re-roll the saving throw.