I'm having a little trouble with learning directions and positions. It seems that most often the word bian is being used to indicate a position: front side 前邊, back side 後邊, etc.
But then I see stuff that uses mian for position: 外面有人吗?
So I'm a little confused as to when I should use bian and when I should use mian. Can you help me come to an understanding of the two?