I'm also only good at coding! I do have some electronics experience, but I definitely don't know it all. I simply look at designs and how they work, and copy it into whatever I make.
anyhow, i own an arduino, basically its USB port is a COM port emulator, so you can send data through the COM terminal of your choice (or use the provided one) and you will receive it via UART, character by character. simply write some code to add all these letters to the end of a string and when it finds no more, you got the mesige!
sending data back to the computer via USB is even easyer, Serial.println("hello world!"); will give you hello world! in the console, when you want it.
if you want to do it yourself, however.. there are probably COM emulators on sparkfun, hookup the thing via UART, and it shud do the same.