Belly pork is naturally fatty, and layered up between the meat, so there's no way you can remove all of the fat... but this is what makes it so wonderfully moist and flavoursome! If you cook it well it will have beautifully crispy crackling on top, and the layered fat underneath will render down and simply melt in the mouth when eaten.
The best way to cook it is to keep it simple:
Rub a little oil over the skin, and then a little salt, and rub it in well. Then simply place in the oven at 220C for 10 mins, then turn the oven down to 180C (170C if fan assisted) and allow to slowly roast - the time needed depends on the weight of the meat you're using. As a rough guide, once the crackling is a deep golden colour, the meat will normally be cooked. If you allow it to rest for 5 minutes once you've removed it from the oven, the meat will relax and the crackling will harden. Yum!
Good luck!