What are those 4 side keys on the clarinet for?

The four side keys on the clarinet are used to play the notes E, A, B-flat, and C. These notes are all found in the lower register of the clarinet, and they are essential for playing many different pieces of music.

The E key is located on the left side of the clarinet, just below the register key. It is played by pressing down on the key with the middle finger of the left hand. The A key is located on the right side of the clarinet, just below the thumb rest. It is played by pressing down on the key with the index finger of the right hand. The B-flat key is located on the left side of the clarinet, just below the E key. It is played by pressing down on the key with the ring finger of the left hand. The C key is located on the right side of the clarinet, just below the A key. It is played by pressing down on the key with the middle finger of the right hand.

These four side keys are essential for playing the clarinet in all of its different registers. They allow the player to reach the lower notes of the instrument, and they also help to create a more nuanced and expressive sound.