proper filing steps

I'm currently a defendant in a civil complaint in district court. My answers and affirmative defenses were filed, then the plaintiff filed an amended complaint adding a second defendant to the complaint.

Now I'd like to file an amended answer and affirmative defenses, PLUS, I'd also like to add several counterclaims. May I just file the amended answers/affirmative defenses/counterclaims since they already amended theirs? Or, because I'm adding the counterclaims, do I have to file a motion to amend and a notice of hearing first?