I like the fact that they not only offer concrete things to say but also some background on how to define your own boundaries and what that means. I know for may survivors, we have to first address the core issue, the elephant in the room, before we can start the practice, so let me just go ahead and say that:
You deserve to set your own boundaries.
Full stop. Let that sink in, let it rattle around in your brain, keep reading it until you believe that about yourself.
Then, go take a look at the practical examples of doing that.
What boundaries do you struggle with? What has helped you do better at maintaining them?