Obtain two small funnels or a chestpiece-like cup
Obtain flexible tubing, about 1 to 2 meters long
Obtain a Y-shaped connector if you want dual earpieces
Obtain two earpieces or small rubber ear tips
Cut the tubing to the desired length
Attach one end of the tubing to the funnel or chestpiece
Secure the connection tightly with tape or glue
Attach the other end of the tubing to the Y-connector
Attach the two earpieces to the Y-connector
Seal all joints to prevent air leaks
Test the stethoscope by placing the chestpiece on a surface and listening through the earpieces
Adjust the fit and tighten any loose connections if needed