You learn special tactics called Formations. You can use a Bonus Action to activate one of the following Formations, which lasts until you and your Allies are no longer in that formation, you have the Incapacitated condition, die, or activate a different formation.
Flank
You can use this formation when you and an Ally that doesn't have the Incapacitated condition are adjacent to an enemy and on opposite sides of it. You can determine this by tracing a 5-foot-wide Line from your space. If this line passes through the center of all three spaces, the enemy is flanked. You and your Ally have Advantage on attack rolls against the flanked creature.
Solo
You can use this formation when you have no Allies within 5 feet of you. While in this formation, if you target a creature with a cantrip, that creature can't make Opportunity Attacks against you for the rest of the turn or until you are no longer in this formation, whether or not you deal damage with the cantrip.
Wall
You can use this formation when you and two to six Allies that don't have the Incapacitated condition are within 5 feet of another Ally. Each creature in this formation (including you), gains a +2 bonus to its AC.