I can't dance, I'm to stiff and have no flow?

I'm trying to improve my lifestyle, last night I went to a party and was sitting on the couch the entire time because I can't dance at all and don't have the confidence to ask a girl to dance knowing that I can't. I'm extremely stiff, and I have no flow whatsoever. Is there any way i can work on that? Also when I'm on the floor, I have no idea of what to do. I don't know what to do with my arms or legs or hips or anything.