I'm not sure how much detail you want to be giving here. I think if you can filter people into the second class jobs they want to be, then mention how useful each of the six stats are for that job. Maybe give some basic numbers and a list of a couple of the most useful skills for that first/second job.
For example a Knight may look like this:
Str - This is the main way to increase your damage, for every 10 Str you get a bonus to your damage, the bonus increases the more you have.
Agi - This determines how fast you attack and also your ability to dodge other attacks.
Vit - This increases your health and how much healing items heal for. It also reduces damage taken and the chance/duration of negative status effects (stun, silence etc)
Int - This increases your sp and sp regeneration rate, this is not very important for a Knight.
Dex - This increases your chance to hit monsters, every 5 Dex grants you a small damage bonus.
Luk - This increases your chance to perform a critical strike and slightly increases your chance to lucky dodge, this is not very important for a Knight.
80+ Str
~40 Dex
Then a defensive stat, either Vit or Agi. Vit Knights generally try to kill many things at once by making a large group and killing them with some area of effect attacks (like Bowling Bash or Brandish Spear). Agi Knights generally attack one target at a time but attack very quickly using a two handed sword with the skill Two Handed Quicken while dodging many of their attacks.
Swordsman Skills. These are some of the most useful skills but levels in the others are required to unlock Knight Skills:
- HP Recovery - When standing still for 10 seconds restores some health, also increases the healing from potions. Very good!
- Bash - A strong single target damage dealing ability. Very good!
- Endure - Allows you to continue running when monsters hit you.
- Sword Masteries - These increase the damage you do with one/two handed swords.
Knight Skills:
- Peco Peco Ride/Cavalier Mastery - Allows you to mount a Peco Peco and attack at normal speeds. A Peco Peco will allow you to move much faster than you would on foot.
- Twohand Quicken - This increases your attackspeed when wielding a two handed weapon.
- Bowling Bash - This hits the enemy you target and those around it twice, very good for killing groups of monsters.
- Brandish Spear - Deal damage to a group of enemies near by. Requires a spear.
God this is already way longer than I wanted and I left out tonnes of stuff, it's very hard to cut things back to the basics and any new player is going to get flooded with information. I think the best thing will be to give new players/accounts plenty of options to correct any errors they make with their character instead of punishing them for it. It's one of the things we like about the game, but its very very brutal on new players who have no idea that luk doesnt increase their drop chances or just how important it is to get enough dex to hit stuff.
You may have to offer some incentives to get people to write out some words for you though, the people who know the things are unlikely to be interested enough to write stuff out. Also an example of what you are expecting would make it a lot easier, providing people with a scope and format that they can copy and duplicate for most of the classes/roles.