You have to tune everything else out. Once you hear it, follow it with your mind and ears. Concentrate, & you will find it. After that, it will be easy for you. If you cannot get it, tell them you just can't separate the two, never just guess. And about the heart sound on a heavy person, they will tell me to listen in a certain spot, but I never do. I find my own way to do things. If they have bigger chest, I usually go under and off to the side. Sometimes you just really have to "get in" there. Sounds odd, but it's the truth! You will get the hang of it!