In fact, all characters are provided in the module. We won't need to make new ones, but there may be some homework for learning AD&D basics.
For the curious:
AD&D is D&D 2.0. We've been playing Pathfinder, which is a modification of D&D 3.5, which attempts to add clarity and balance to some odd rules from the source system. 3.5 was kind of broken because anyone who could cast spells ended up being very overpowered toward the higher levels.
If 3.5 is unbalanced, AD&D is a battle royale of toddlers and gladiators with very real threats. Death is not uncommon. It's a good thing the module provides 8 characters, because we may need to use some as backup.
One of the great things about AD&D, and in particular the module Eric has chosen, is that they embody the "original" feel of the Gary Gygax-era D&D game. There is no balance in a Gygax world. He lived in a Tolkienesque world where meek hobbits were heroes, and powerful warriors and wizards rose to great deeds as often as they succumbed to temptation and died. Role play is a major focal point of that game, but not to the extent that you must embody a character, just that you must enter the world. Your decisions carry mortal weight, and you get no take-backs.
Once character choice comes up, you'll want to pay close attention to their abilities, their role, and their background. Goran, there's a nice and powerful Paladin in there with your name on it.