It's unclear to me when and how this move should be used.
On paper it reads like an awesome way to abstract an otherwise chaotic situation, but the more I try to figure it out at the table, the less I think I understand how to use it :P

On one hand it looks like a pre-move, something you roll because of the situation to see what is happening around you and to you BEFORE you get to describe your PC's actions.
But this puts the move before the fiction: how are you stirring up the chaos? how are you calming it down?

Maybe you handle it like Read a Person? Triggers thanks to minimal fiction (you observing someone) and adds detail when you actually select the questions you want answered. What are you looking at? How are you observing? What are you saying to prompt the answers you seek? etc.

How often is this move meant to be rolled?
One of the results allows the performing of "one short action" ... is this the limit before the Free-for-All is rolled again? Or is it just a beneficial effect (making an action unopposed) but the PCs will otherwise be able to make more actions against normal opposition and obstacles before, after an MC chosen amount of time, the Free-for-All move triggers again?
Or is this wrong? Should the players FIRST describe what their PCs are doing within the chaos and THEN roll this move?

Is it possible to use the "calm down the chaos" effect to factually stop the chaos? Maybe reducing the chaos-gang Harm to zero? Or is this effect not cumulative?

And WHO is rolling the move?
If all PCs involved in the chaotic situation roll, can they select the same effect? Will this stack? Can this ramp up the Harm inflicted to crazy levels, or cool it down to zero?
And... is the crowd inflicting Harm to itself for EVERY roll?
This last point leads me to think that the move is meant to be rolled ONCE for all PCs involved... but then, who gets the benefits? who can act how? and whose stat is rolled? who gets to roll the move while the others maybe interfere/help?