How to do lateral medicine ball slams: Stand with your feet about shoulder-width apart with the medicine ball on one side. Pick up the ball and simply rotate your body as you slam the ball a few inches away from your pinky toe. Make sure to pivot your feet and bend the back knee as you come into a split squat position to catch the ball on one bounce. Alternate sides. Make sure you tighten your core as you bring the ball overhead and to the side.
There's no way around the fact that, when it comes to burning more fat, you have to work at it. There is no magic exercise, workout, or pill that will do the job for you. The good news is that it doesn't take much activity to push the body into that fat burning mode. Try incorporating some type of activity every day, even if it's just a quick walk, and build on that over time as it becomes more of a routine. Do that and you're on the way to burning more fat.