You can build an adaptive mapper, you will just have some accuracy problems, as you lack encoders. Well, this is assuming you do have wheels (not listed).
Take a look at Admin's Wavefront tutorial, it's great for beginners.
The reset button interrupts and restarts your program. It's generally used as an alternative to disconnecting and then reconnecting the battery.
You don't need to copy the bootloader - its on your computer already. Use a hardware programmer to write it from the Arduino IDE to the ATMega328, or put the ATMega328 on a breadboard and use the Roboduino as a programmer (will require a number of passive components).
You will also need a base for your robot, though a cardboard box would work just as well as a fancy laser-cut chassis in the short term =).