The Bitcoin network is run entirely through mining. Mining is the process by which computers solve algorithms, and when they find a block they get the block reward of 25 Bitcoins (worth $15,500 currently). Usually miners pool together their resources and receive shares of the block reward proportional to their mining power, since when mining alone it's extremely rare to find a block even if you own hundreds of thousands of dollars of mining equipment. When a block is found all transactions included in that block are confirmed. After receiving Bitcoin you cannot send it anywhere until it is confirmed at least once, so mining is essential for the Bitcoin network to keep running. On average there is 1 block found every 10 minutes, so it takes on average 10 minutes for a transaction to become confirmed. Confirmation time can vary wildly though, from less than a minute to several hours.