To release your Free Bets, you will then need to place qualifying bet(s) to the value of your deposit (up to a 10 cap or currency equivalent) and allow the bet(s) to settle - they must settle within 30 days of claiming the offer. Once your qualifying bets are settled your Free Bets will automatically become available.
However, winning too often will see your account with bet365 restricted. This is why bookmakers don't like professional gamblers who consistently win. It is bad for business, and bookmakers are out to make money, not lose them.