Uploading a facebook video to youtube!!!?

Ok so my best friend is a singer and wants me to start up a channel and post vids of her singing on it. I agreed and she wants her first video to be one that she uploads to facebook. However, I do not know how to take the video she posted from facebook and upload it to youtube. I don't know how to save it to my computer it wont give me an option please help me it is rather important!