Character Animation Setup Problems

I use a bibed character. It has a sword that I want to animate, I don’t know how to animate it. I have tryed to parent it to the character, but if i want to make it posible to put it down, it won’t work because of the parenting. :(Can someone please tell me how to set up for an animation.

The constraint that does the job is called Child of.

Thanks. stall try to use that one