Alright, a lot of things involving what you find in the labyrinth are explained in the game. For the most part, everything in the instruction booklet can be understood very easily from looking at the respective part of the game - how the town works, what commands do in battle, all that jazz. Even the skill tables can be discovered by just trying out a new person in that class and looking at the list of skills (the one in the instructions are just names, no descriptions).
There's a lot more to be learned, but that is primarily stuff you'll remember from the first game or will have to find out on your own (Or, you can ask us here!)
Aside from the Stats and the Ailments, the only other thing in the instruction booklet is a little story at the end. But it's non-essential and mostly serves as just a flavour element to close the book with.
I actually never realized they tried to explain this.
- ATK: Based on your weapon, and your STR stat. Deals damage.
- DEF: Based on your armor, and your VIT stat. Reduces damage.
- STR: Affects attack power
- TEC: Affects the power of various skills
- VIT: Affects defense
- AGI: Affects turn order and ability to evade attacks
- LUC: Affects your chance of finding items
Only Death and Stone last after battle. Game over happens if everyone is Death and/or Stone.
- Death: HP is 0, character is incapacitated
- Stone: Character is a motionless statue and takes less damage.
- Sleep: Can't act and takes extra damage from attacks. Getting hit cancels this.
- Poison: Takes damage at the end of every turn.
- Confusion: Can't be issued commands, will instead blindly attack, possibly attacking allies.
- Curse: Take damage when attacking equal to half the damage dealt to all targets.
- Blind: Reduces accuracy.
- Paralysis: High chance of not acting each turn.
- Terror: May not act every turn due to fear. Some of a Hexer's special skills require the opponent to have this status condition.
- Bind Head: Cannot use moves that require sight, speech, or thought. Also reduces accuracy.
- Bind Arms: Cannot use moves that require hands or arms. Also reduces physical attack power.
- Bind Legs: Cannot use moves that require movement or legs. Also reduces turn order and prevents that character from using Escape.
Anything special about a particular FOE will be explained in the story. Including the ones that are not important, they will be quickly explained to be little more than big monsters that want to kill you dead. And will do so with ease.