I know my way around the grappling mat and can spot a good teacher on Youtube and can immediately tell which videos to ignore, but I'm fairly clueless to the stand up game. I can't tell who is legit and who is a bum that happens to have a smart phone and can make videos. I'm guessing there are a lot of the latter. I'm looking for a good tutorial on how to effectively use the heavy bag. The objective is to get a good conditioning workout and improve my striking. (Would also like the same for focus mitts, if possible.) Suggestions? Many thanks.