Well, you'll probably have lots of luck here.
You might just want to ask your brother for help, in case he does anything special, or wants to help you create a character himself. (I dunno, I really liked helping my brother create his first character, but this won't always be true, etc.)
Anyway. What do you want them to do? Anybody you're trying to emulate, what's your idea for the character, etc?
For instance, if you were making a rogue, you could say "I want a sneaky guy who will avoid being seen by enemies until it's too late," or "I want a fast talking halfling who manages to get by through duping everyone," or "I want to be an ex-assassin who has reformed his ways and is trying to walk the straight and narrow path, but keeps slipping."
That sort of thing.
There's also "I want to be the best bowman in the world," or "I want to be able to scream, and then tear a bear's forelimbs off with one arm tied behind my back," or simply "I want to make things explode with my mind," or "I want to control armies of the undead..."
But if you just need stats...
Do you want the ranger to use two weapons or use a bow, or do both of those, or do something else?
Do you want the fighter to use a polearm, a sword and a shield, a two-handed sword, two swords, a bow, or something else?
Do you want to be good at special manuveurs, or just hit stuff?
Your best bet might just be to look in the player's handbook, look at the starter packages for the classes, and ask your brother to help you level them up to level 2. He might not be giving you normal amounts of gold for level 2, etc.
I hope at least part of this was helpful. If you just get a line for what you want out of your fighter and ranger, that might help things quite a bit. Stats are easy to chunk out, but it helps to have a tiny bit of direction, etc, other stuff... goodnight.
If not it's going to be a little trickier.
