There's not too much to it. Download the casino. Sign up as a real money player. Deposit $200 using any method other than Neteller. You will immediately have another $200 added to your account for a total of $400. Play small bets. Maybe $4 to start with, less if you want to be even safer. Keep track of your wagers either with a clicker or just by putting lines on paper. Remember to include splits and DDs as wagers. Once you've wagered over $4,000, wait a couple hours because they don't update it immediately, then withdraw whatever you want. You can leave money in there if you'd like to actually gamble some more, but I'd only recommend that if you've made more than just the bonus (a balance of over $400), and maybe not even then.
One word of warning of though, the software that they use is very slow compared to every other casino at which I've played. It could take a while, and I don't suggest you do it all in one sitting. They also take longer to pay than most others.
Other good places to start are Bet365 (same terms, MUCH faster play), Starluck and Planetluck ($100 bonus, $1,600 WR).
Good luck, let us know how it goes.