about this – what is the historical or traditional occasion and context for this type of performance or dance, what is the song, whether there are lyrics or other signifiers and what their meanings are, to what extent are there prescribed steps or patterns, is there a prescribed length or a leader who gives signals, the nature and meanings of the costumes, etc.

"One of the oldest surviving Northern plains dances, the grass dance is a popular feature at powwows. Requiring a high level of flexibility and athleticism, it is a dance often chosen by young men who have a certain someone to impress."
https://www.wernative.org/articles/men-39-s-grass-dance