Agitator replacement for Whirlpool

I am having trouble figuring out how to replace the Agitator and dogs. There are no screws or bolts that are holding it in. It looks like just a plastic piece is snapped over it and holding it together, so I tried pulling that out but no luck. I have to take ithis plastic piece out to get to the parts that are screwed up to put the new one in. Any help?