LDing isnt allways about having controll of a dream, some people are happy to just have a dream and be aware their dreaming.but usually when people realise thay are dreaming they they can just suddenly do what they want in it.
dreams are all in your head, your mind allways controlls them one way or another.The difference betweem a normal dream and a lucid one is that in a lucid dream its the concious part of the mind controlling the dream.