I actually imagine that there would be a lot of similarities to the structure of already existing anarchist organizing, particularly street antifascism.
Usually people will meet ahead of an action and discuss likely events and how to respond. If things happen that weren’t predicted, it relies on the initiative of people on the ground.
Usually people with experience will end up making snap decisions, though people will occasionally veto them. If there is an opportunity, the people who disagree will huddle and decide on a new course of action. If not, someone might just call it out a new course of action, which people will also sometimes veto.
I’m personally quite a fan of simple instructions that you can chant because it also boosts morale and demonstrates unity to the opposition.
At a recent example that I think was particularly effective, a group of spotters* were following a fascist march, one person shouted, “Come on guys. We can’t let them go unopposed.”
A second person indicated that they agreed by proposing a strategy, gesturing to link arms, saying, “Link up.”
A third person adapted that into a chant of, “Link your arms! Stand your ground!”
Spotters are a scout-like role who usually have the responsibility of keeping an eye on the opposition and relaying that information back to the action itself. In this case, the spotters realized that remaining as spotters was less useful and adapted accordingly, since the main counter was trapped elsewhere.
Interestingly, as the police decision makers were with the main counter, the police who were with the spotters were unable to act because their structure depends on a hierarchy whereas the adaptability of anarchist organizing doesn’t.
I monitor far-right groups pretty intensively and a good chunk of Paedophile Hunters are key organisers of said groups.
Its also not uncommon for far-right groups to be family operations where the adults will groom their teenage children into organizing and encourage their children to date other, often older, fascist organisers.