Hi Karyn, please don't take this as an attack, I know you're getting a million conflicting messages about racism. I know it must be frustrating constantly being told you're doing it wrong. I know you're genuinely trying to help. But let me say this:
You're not that important.
What I mean by that is that your complacency has had absolutely no impact on the systemic racism I or other black people have suffered. You're not to blame. You didn't build these systems. You didn't ask for them. There are plenty of black people more guilty than you are for perpetuating them and plenty of others doing less than you are to tear them down. Don't try to carry that responsibility.
If you want to help, examine yourself. What are your prejudices? What are your biases? Do you turn a blind eye to racist comments when there are no people of colour around? Do you react diffently to a black person walking behind you than a white person? If so, then do the best you can to change that.
Also, you don't need to explain things on our behalf. In my opinion, black people who refuse to talk to white people about race are a part of the problem. Of course, some disagree with me. That's the point. There is no singular "black truth" to explain to other white people. Say it how YOU see it. Do the best YOU can. Be willing to change your mind, but don't be bullied into doing so just because a black person tells you to. Ask questions, challenge assumptions. Black people can be wrong too.
Again, please don't take any of this as an attack. It's genuinely heartwarming that you care enough to try and to ask for advice. This is mine. Others will say different things. If you care about fighting racism, and you clearly seem to, then trust yourself a little more.