Undo/Redo:  Use these to undo or redo the action listed.

Important: The following items respect the Active Key Edit and Channel Group settings.  Be sure you have them set the way you want.

Create/Delete/Move Key:  Use these to bring up their respective pop-up windows.

Bake Key Range:  This brings up a pop-up window where you can set a range (using the In and Out fields) to bake the frames.  Baking  will "lock" the motion onto every frame.  In other words, it will put a keyframe on every frame within the range (the In and Out).  The pop-up window allows you to set the In and Out point that you want to bake between.  You also have the option of turning on Use Computed Values, which will take into account external things that have an effect on the motion, such as expressions, Compose, etc.

Erase Key Range:  This brings up a pop-up window where you can set a range (using the In and Out fields) of keyframes you want to erase.