What is being depicted w.r.t. AoA in this video? I was looking at this video of the AF447 crash simulation and at about 4:45 the angle of attack diagram shows a few things I don't understand (frame above).

I get the orientation of the airplane, pointing a few degrees above the horizon, but what does the green line represent in layman's terms? Is that the direction the plane needs to go for the wings to generate lift?

Also, I see the red line has to do with the warning, but how does that play into it as well?
There are several colored lines.  Which one are you asking about?  I'm assuming you are referring to the (cyan?) and red lines in the upper right inset.



The cyan line shows the current direction of the airflow.  When compared with the orientation of the airplane can show the angle of attack.  At this time, the relative wind is coming at a very steep angle to the airplane and the wing is stalled.

Another way to see it is that reversing this arrow shows the direction the airplane is moving through the air.  In a no-wind situation, this would also be the direction the plane is moving with respect to the ground.  

The red line is at a constant angle with respect to the airplane and shows how low the airflow can go without causing a warning.  As it is below this line, the stall warning has sounded.