Place the mouthpiece over the cork on the end of the instrument.
Push the mouthpiece onto the end of the woodwind instrument gently, with the reed part of the mouthpiece facing at a 45-degree angle from the floor.
Twist and push the mouthpiece onto the neck of the instrument, turning the mouthpiece until the reed is parallel to the floor, when the instrument is in playing position.
Hold the mouthpiece by the rim and place the pipe on the end of the instrument inside the lead-pipe of the horn.
Twist the mouthpiece to the left while you push it into the horn.
Check the mouthpiece fit by gently pulling out to see if the mouthpiece falls off. If it does, you need to return to Steps 1 and 2 and use more force.