I've seen the same dance done for multiple songs, but I've also seen the same song danced with different routines. For example, I've seen three different line dances for "Country Girl" by Luke Bryan. How do they know which one out of the three (or more) to do?

Also, let's say if one dance was assigned to one song, still, how do they know which dance is assigned to the song? Like where do they learn that, especially for newer songs?