By default there is only one shapekey which is the one used for the "wide mouths". You must add more shapekeys depending on the expression you want.
261 days ago (+1)
By default the mouth is disabled, you must check the property "Mouth" in the Pivot_Mouth bone. This option is in the panel that appears when pressing the N key.
I'm not sure if this is what you mean.
I have tried to change the sharpkey but it's not working