Stethoscope - can't hear anything?

If you're a novice - make sure it's turned on (rotate the chestpiece and tap on diaphragm). The pressure you put on your diaphragm can affect the sound - press only lightly to ensure good contact but don't push on the chestpiece. Make sure the earpieces are facing forwards in your ears. Try different eartips if you have them - sometimes hard -v- soft affect how well you hear for different people.

Lastly, in a quiet environment, listen to your own chest. You do need to move it around to find the best spot to listen (2nd ICS, right or left sternal border; or 4-5th ICS, left sternal border; or apex at 5th ICS, midclavicular line). You do have to concentrate to hear what you need to hear.

A lot of it is practice.

I have the same scope, the end actually turns so you can use the bell. If it is turned the wrong way you won't hear anything. Also make sure the earpieces are on right. Otherwise, you may be pressing too hard or listening in the wrong places. I love practicing on my children because you can hear their heart a lot better. Good luck.