Animator doesn't save my animation.

So im using the third person controller starter assets and i was just messing around with it. I wanted to create a sword attack animation, so i opende the animation tab created a new animation clip and selected the right upper arm transform.rotation and added a key frame (while recording). I only change the rotation of the arm but whatever i do i cant save it, it just instantly changes the rotation values back to what it was. I created a cube and tried animating it, it worked perfectly fine, as it should. But i just cant create a new animation on the rigged character asset. Can someone please help?

Turns out i cant animate humanoid characters in unity :frowning: