[Remember that the temperaments of different cities in regards to criminal law and legal matters varies, and it is important to have knowledge for your specific area, or the specific area where you are acting. Much of the material that follows is New York or Ohio Specific, and none of this is legal advice; and also remember never talk to the police.]
Here are all the more or less current Know Your Rights (KYR) things I can
think of, attached or as links.
The way I have always done legal support for protesters is to educate
people using these, and at the same time, either be or find a lawyer who is
not only licensed in the state, but actually familiar with the local
courts. It is crucial to actually find someone who is qualified (like,
don’t get a housing attorney to advise you on criminal defense matters) and
politically on board (someone who actually knows and cares about the nexus
of expressive rights and criminal defense).