Hi, does anyone know of an easier way to trill from A to B? (I don't know the official name for the register, but it's the B is the first note that needs the register key). Because I know some notes have alternate fingerings, but I couldn't find it in my book. Thanks.

I'm going to second the top two keys trill.

okay ill try to explain it. hold your clarinet like if you were to play a Bb or a A#. you know that wierd key when you play an Eb? there will be four to its side. To trill A to B, Blow in air while playing an A. Then move your finger to the register key and at the same time press the key second to the top of the four "wierd" keys. Yes i know its confusing and quite hard but youll get used to it.

Oh thankyou, that was very helpful!