There are two possible answers. The first one is that everyone will help by following orders and just doing things on raids in the right way.
But if you're asking that question, you probably want to do more than that. In such a case, talk to our usual raid leaders or officers (again, not during a raid) about it. There are a lot of tasks that need to be done on raids (like loot handling, organizing healers or tanks or other classes, scouting before raids, and so on) - and volunteers to perform some of them are always welcome.