Anyone know of a good site or link to explain this?

I am studying for an anatomy test(college level) and I still can’t seem to grasp how blood flows through the heart and all of its components. I have looked for videos online(youtube) but, none seemed to really help, do any of you flutherites know where I can check out a video(preferably in french, since that’s the language I study in, but I’ll make anything work!!) that will help me out?