It should be enough to get you started, but better read some more elaborated guides.
Okay, let's go.
There are 4 standard classes in the game: Warrior, Magician, Bowman and Rogue.
Though in practice "Rogue" class has two subclasses that are completly different: Dagger Thief/Rogue and Throwing Star Thief/Rogue.
When creating a new char, you get to determine:
Name. Maybe it's just me, but I suggest you spend a while on inventing a good name.
Some tips: if you want, for example "Naruto" and you find it's already taken, don't just take "Naruto7836", it's ugly, better rethink the whole thing.
Using upper case i, to replace lower case l, or vice versa is illegal (!) and can get you banned!!! (Though, why won't they just change the font used, is beyond me >_>)
Then you choose your face and hair, that's very important, because it will your stay your look forever, unless you spend real money(3 dollars or more!) to change it.
And then you can roll the dice to change your starting stats.
Do not ignore this step!!!
In MS each class has a main stat and secondary stat, and the other two are almost useless for that class.
That's why you decide on a class first, and browse a class guide, so you know what stats you need while rolling. Since the dice always add to 25, just keep rolling until you get 4 or 5 on both of the stats you don't want.
You can also customise your starting equipment, but don't bother, you'll sell it and replace in shop within a couple hours.
I suggest you create the first character just to look around, try different things, gather some money and get the feel of the game, possibly find some traps the hard way.
Get this first char at least to level 20 or so.
And then create a character you will attach emotional weight to/ identify yourself with.
That first character should be warrior, as they are easy to level early on, offer lots of resistance, and they get bigger carrying capacity, so your first char can later double as a "mule" (a char you use to store pricey stuff, not to clog your main char's inventory)
Anyways, to help you decide on a class, I present you with short characteristics of each class, these should give you a basic idea of what to expect, and should let you choose a class that will fit you.
Warrior and Dagger Thief are the two melee classes.
Warriors: resistant armor, lots of HP, strong attack. Various weapons available.
Thieves: agility, speed, lots of stabs delivered with lightning speed.
And then there are 3 ranged classes:
Magician: quite strong magic attack, that can attack when in melee too+ magic guard that protects you from damage.
Magicians get powerfull very fast. But they slow down later- other classes buy new equipment that multiply their powers, while magicians are stuck with the same spell. (New wands and staves offer little bonus)
Bowmen: Bow/Crossbow can be swung when in melee, knocking enemies back. They also get critical shot skill that adds damage. For an unknown reason they aren't too popular.
Perhaps because in second job they are just strong ranged attackers, while Thieves and Clerics get some party friendly support skills, and Magicians are, well, Magicians, and even though they are starting to fall back on damage, their fame from first job carries on and everybody wants to have one around.
StarThief: Use throwing stars, but when a monster comes close, they can't throw and have to punch for pathetic 1-5 points of damage. Fortunately they get invisibility skill that helps them out. They can also jump and throw stars when in mid-air.
StarThief (aka Assassin) equipment is complicated AND expensive.
Note: No class is "better" or ultimate. They all have their moments, and the choice should be based on your personal prefference.
For example, I preffer ranged attacks, and hence I elaborated on ranged classes more, but melee chars are good too, I just don't play them too often.
Read on in:
Skill and Ability Points allocation guide (Melee)
and
Skill and Ability Points allocation guide (Ranged)