i googled the "breadboard robot" and find this interesting robot. Hope it will help you.
http://www.instructables.com/id/Simple-Robotics-Breadboard/
BTW, you can also refer to Cytron's DIY project no.23, PR23-multifunction mobile robot. The software and schematic are all provided free. If you want simple, you just focus on some part like motor driver, microcontroller basic circuit, push button, two dc motor and line following circuit if you want it to line follow. The rest of circuit you can ignore it.