What will happen when my havana bunny gets ready/gives birth?

I am a first time bunny owner. I have a 1 year old havana bunny. I didn't know she was prefnant when I got her til I seen how BIG she was. I don't know how far along she is. Like I said I just got her today. She is olnly laying in one spot and if we try to pet her she gets very jumpy. How many babies will she have? What will she do before gives birth? Do I need to do anything?