A brief explanation of Bitcoins
Bitcoins are a new form of digital money. It's not like PayPal (which is based on regular money), Bitcoins actually are the money. The Bitcoin "money" actually exists on your computer in a "digital wallet." You can also have wallet websites hold the money for you, like "digital banks." Bitcoins work because two people agree to make a deal. If I have some Bitcoins and want to buy something from you, I send you the Bitcoins from my wallet to yours. That's it.
The question is, "Where does the digital money come from?" The answer is, "People make the money on their computers." This is called "Bitcoin mining", like gold mining back in the old days. Bitcoin mining is what can be done with the Bitty Miner app.
To see the steps of how this is done, go to the setup page.
A detailed explanation of Bitcoins
A great place to learn more, with much more detail, is weusecoins.com.