When you link the upper and the lower joint bridge keys together, first place your hands so your left index finger and your right index finger (or right middle finger) can play the alternate Eb/Bb fingering Eb/Bb. When you assemble the instrument in this way, if you find the alternate Eb/Bb fingering doesn't make a sound (or it is difficult to make a sound), it likely means the instrument was not assembled correctly. Please visit the following site for more details on how to assemble your clarinet:
http://www2.yamaha.co.jp/manual/pdf/wind/english/clari/Clarinet080620_English.pdf
