Kind of a stupid question but........

I’m pregnant with my first baby but I have kind of a stupid question...in looking at birth videos I see that the babies are only wiped probably with a towel or something and a hat is placed on their heads because I understand babies tend to lose body heat fast(if I’m wrong please correct me)...my question though is at what point do they actually wash the baby to remove all of that white stuff from their skin and how exactly is it done?