First of all this description is short. I try to give ya the most important informations about lux in this build.
Sorry for some gramma mistakes, my english is not the best :)

Don´t know if its the right chapter, but who cares ;D
clarity is most important.
The items don´t support manareg or mana. It´s not needed and you can save the money. But you have to use clarity in the right time.
I think i don´t need to explain Flash. ;D

Only one thing to say. ABILITY POWER.
If all works fine, you can reach an ability power of 800. And your ulti will kill each lowlifechamp by 3 attacks.

STAY in the back. Your range is incredible far, and if someone is near ya you are fast dead.