Let's Make Robots!

Autonomous robot navigation

Hi guys, I am having trouble working out how to program a robot to be able to navigate itself around a small area. This is the first time I am building a robot and I am at a loss on how to even begin, and google hasn't been much help ever =\ The only idea I have is to program kind of a "virtual map" in the robot and some how make it keep track of its movements. I am wanting the robot to be able to work out how to return to a particular location too. Any help would be appreciated. Thanks!