A good start is to read the articles available on this web site. Click the "FAQ" and the "Robot Tutorials" on the upper right of this screen.
Then do Google and Wiki searches to learn more details about terminology. Example: "RS232", SPI, etc.
Also, reading through the threads in the forums here will expose you to many ideas and methods for building robots.
Lastly, Post questions here when you really can't find the answer or ideas when you are ready to start building your Bot.