Commands are instructions given by the player to their team.
In the Beginning
At the start of the game, players must manually control themselves and their familiars in battle. This method works when you only have yourself and your one familiar to worry about, but as you progress through the story, you need to employ TACTICS!
Upon receiving your second party member (Friend, not familiar), the player opens up a new command window called "Tactics". The tactics menu allows you to fine-tune your party and their actions. Do you find that they are using all their mana on small time kills and then have nothing left for bosses? You can remedy that situation and others within the tactics menu!
After progressing through the story, a player will unlock two additional battle commands for their team: "All-Out Attack!" and "All-Out Defense!". These allow the player to take immediate battle control of their team.
Is the boss vulnerable? "All-Out Attack!"
Is the boss charging up a large damage ability? "All-Out Defense!"
The Finer Points
All Familiars can participate in an "All-Out Attack!" but NOT all familiars can participate in an "All-Out Defense!".
Familiars with the trick "Psych Up!" do not have a natural defense and thus they should be used sparingly on your companions familiar squad should they need to participate in an "All-Out Defense!" call.