How to follow a line while moving in (x,y) plane?

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"Question 1 - The vector holds sequential X,Y coordinates for the camera." If he wants to get the coordinates of the camera, he can simply read the central pixel of the image, since the camera is facing it.

"Question 4 - There is a way to transform X,Y coordinates from the contour to camera coordinates and finally instructions to the motors."

From my binary image, i can get the angle of orientation of the line segment, but that isn't enough to drive the motors, i need to decide which way i want to follow the line, CW or CCW, how can i do that? and how did he do that?!
.. Any details are much appreciated.

Question 1: I meant the XY coordinates for the camara's future position, not current position.

Question 4: I think that he calculates the centroid point of the current line being followed, and the correct travel direction is always towards that point.

So the edge of the ROI is where the center of the camera needs to go? Indeed he needs to always centralize the camera on the line being followed. What about the phrase: " In my direction of travel I set a region (30 degrees) either side of that point and disregard anything outside of it." ? I'm trying to figure out from where to where is this region of 30 degrees, any ideas?

I can't fully understand that statement either. But I am assuming that he discards most of the image and analyses just a small portion of it (ROI) around the center. Normally ROIs are defined as offset coordinates to a certain point, not by a measure of degrees..