Lie follower without mc

Hi..
This is my first robotics project.
I am taking part in a competition where I have to build a Line Follower bot without using mc
I am a 2nd year engg. student & I dont know much about electronics.
I have searched a lot in the internet & I have got a few circuits as well..but I am unable to understand them.
I realize that if I can make those circuits my problem may be solved but ultimately I wont get the knowledge & this would not serve the purpose.
So I would like to have a detailed tutorial on this & any suggestions will be helpful.
Thanks.

Try David Cook - Robot Room: Robotics, Electronics, and Schematics