What is the main conflict in The Devil Wears Prada by Lauren Weisberger?

Andrea interviews at Elias Clark and learns that Miranda Priestly, the Editor in Chief of Runway Magazine is looking for a new assistant, a job, Andrea is informed many times over, that a million girls would kill to have. Though Andrea is not sure that being an assistant is what she wants to do she finds out from Emily, Miranda's current assistant, that if someone works for Miranda for a year and does well, Miranda considers them ready for promotion and helps them find the position they are for. Meeting Miranda, Andrea is pleasantly surprised by the grace a woman with such power shows and is pleased with how the interview goes.