How to use the pronoun "en" correctly?
The pronoun "en"

sergio-s5
May 30, 2013

toru e
May 31, 2013
Have you worked through Lesson 6.11/All Important Keys (Part 1) yet? That has some examples of the way *en* is used.
I think you're asking about when it's used as an indirect pronoun - there's a stated or implied "of it" - in this case, it goes before the verb.
Ex:
J'en veux - I want some (of it).
Qui en a assez? - Who has enough of it?
FYI - There's another lesson in Rocket French Platinum on Y and En (Lesson 19.7), but it focuses more on the nuance of using *le/la* vs. *en*.
Ex:
If someone says, Du pain ? (Some bread?)
The answer is either: Oui, j'en veux (Yes, I want some) or Je n'en veux pas (I don't want any), not Je *le* veux, which means you want the whole bread.