Early on, you will need to be able to have information on:

1. Deities and religion. (We have a pantheon of 17 core deities, one for each of the planes.)
2. A calendar.
3. Which multiclass and dual-class combinations are legal. (We allow all combinations as long as two classes of the same base class aren't mixed.)
4. What alignment looks like, and what in-world effects it has.
5. Where silver and cold iron weapons can be obtained.

Later on, you will want to have information on:

1. The number and nature of the suns, moons, and and any other relevant planets.
2. The nature of magic. Especially how druidic, paladin, and ranger magic works in your milieu.
3. How magic item manufacture and recharging magic items will work.
4. How do class-related guilds and organizations work, such as the thieves guild, assassins guild, druidic circles, and paladin orders.