so yeah, type-0 is confusing.
Also don't only play the main character you'll be lost even worse if he gets downed and it makes you switch. Once they are down, they are dead for the mission and you have to pick reserves.
I recommend going to the arena when it opens and try training with every character, use their weapon a lot of different attack styles, you may find a character you like better than ace, I like the Dragoon (forgetting his name at the moment)
You have abilities and magic, and you goto the red crystals to "promote" to use AP to unlock abilities and magic, and yes only two can be equipped and mapped.
The yellow bar is your stamina, certain attacks drain that bar, and make it recharge slow. Abilities use that, instead of MP.
When an enemy is down, if you continue to lock on to them, they will float slightly, tap square again to absorb their magic essence. This you can use later to upgrade your magic.
invest early, in dodging and moving quicker.
The red mark, is a knights-kill mark, if you hit when its red it insta-kills trash mobs, or critical bosses, its random, and for ranged weapons, its lame.
Also ace's default cut cards ability is horrible, I forget the name of the one I user, it shoots a straight beam, I can cast 3, and it brings down those stupid mechs right away. dodge, dodge dodge.
Some missions their are enemies that you can't kill, and you wont realize it right, away, and will one shot your characters, better have someone else you like to use somewhat leveled.
Those are my tips,
I feel meh, so far about the game. Maybe it'll improve, maybe I'll go back to Andromeda that I just started end of July lol.