To prepare to play the clarinet, assemble the various sections of the instrument using a twisting motion. Attach the upper and lower body sections, then the bell and barrel/mouthpiece. Wet the reed by soaking it in your mouth before placing it under the ligature on the mouthpiece. Form an embouchure by stretching your bottom lip over your teeth and sealing your mouth around the mouthpiece. Assemble the full clarinet and you are ready for your first note.