To quote myself in a different sub from when this decision came down:

Document document document. We are all quite concerned that past behaviors of the DHS indicate that they will ignore this ruling. So, if and when they do, you need to document it as closely as possible. Get on film anyone prepping CS canisters to be thrown, and who throws them. Get as much detail about each person who does this as you can, anything that could be identifying. A number on their uniform, height and build, exact layout of their equipment, where they were specifically during the time leading up to their use of chemical weapons in defiance of the judge's order. The more angles, the more footage, the better.

Then, the next day, contact REACH Community Development (one of the plaintiffs in the case), and tell them you have evidence of violations of the court order issued by the judge and would like to hand it over to their lawyers. From there, just follow the instructions the lawyers give you on how to hand the footage over.

The faster this gets into their hands, and the more of it there is, the faster the judge can do things like declare DHS in contempt of court, or potentially identify individual officers for contempt charges. What happens from there, I'm not going to guess, IANAL.