The best way to lose belly fat is the same as the best way to lose fat in general. We can't decide where to lose fat we just have to maintain a caloric deficit (burn more than you eat).
Many ways to do this but it's best to focus more on how you eat than how you exercise.
Cut out liquid calories like coffee beverages and sodas and juices. Cut out added sugars in foods. Try to eat clean, less processed pre-made food and more vegetables.
One thing I'd like to add is that cardio is not necessarily the best way to burn fat. HIIT is awesome but a little tip most people don't know is that while building muscle, the more muscle you build the better your body does at burning muscle. So if you work on toning areas and building a little muscle in legs, arms, butt, abs, and thighs, you'll also burn fat as well. Cardio does help with burning calories but toning and muscle building work better. Hope this helped.