Recent large-scale hacks at Target and Neiman Marcus are a reminder that credit card theft is a growing issue. Hackers find a way to install malware on point-of-sale devices, and then sit back as the credit and debit card numbers stream in.

But who are those hackers, and what happens to the numbers next? Here’s a breakdown in four easy steps. (But don’t try this at home.)

Step 1: Build your criminal network

The basic idea is that people use stolen credit cards to buy stuff. Sure. But if the same person stole the card numbers and bought the stuff, they would be easily caught. Instead, baddies create rings. There are the people who buy and sell card numbers in online markets, sometimes called “carding forums” or “card malls.” There are the people who actually make fake cards. There are recruiters who find people to make purchases with the fake cards. And then there are the folks who actually go to stores carrying the counterfeit cards and attempt to make purchases. That’s a lot of people!

Step 2: Create your workflow

The logistics must be worked out carefully. The counterfeiters need equipment to print the cards on, which costs about $100. The people who buy and sell card numbers need to understand how the numbers are constructed, to get a good price for the numbers they have to sell, and to find good deals on working numbers—meaning those that don’t yet look suspicious to financial institutions. Thousands of lousy card numbers will sell in a block for something like $20, but good numbers, like those stolen from Target recently, could sell for $135 each. The recruiters have to have contacts in the right places (a lot of cyber fraud originates in eastern Europe, for example). And finally, the buyers need to feel confident looking a cashier in the eye. They must be trained in what can go wrong at the register and how to deal with it. (The buyers are also frequently the ones who resell the merchandise.)

Step 3: Buy stuff

Once everyone is in place, it’s time to shop. Often criminals are using their stolen card numbers to buy items that can easily be flipped on websites like eBay. Luxury items, popular smartphones, or anything else with high resale value is appealing. The bosses running these operations want to get as much money out of the goods as possible so they can pay for the equipment and “employees” involved in the operation and then pocket the rest.