Yank out the cup from the top.
get the bolt cover off next.
using a socket and extention remove the agitator bolt and washer.
remove agitator.
Place agitator on floor and hold base with feet.
Give top of agitator a yank. It will come apart.
Get all the worn out doggys out of the cam and replace them.
Line the top up with the bottom and snap the agitator back together.
re install the agitator. Easy fix. What can go wrong? If you are not careful you will break the tabs on the base that hold the top in place. Not good but not the end of the world. The agitator nut will hold it on in a pinch. Speaking of the agitator nut. Over tightening it will only cause misery,break the washer and generally make the agitator want to dance loosely in the tub. Not good.