As we've defined it, anxiety is that uncomfortable feeling you get when you think something "could" go wrong. It is the dread that arises not from a real lion in your room, but the worry that there could be. It is the anticipatory worry that life will not go the way you would hope - from having friends to doing good work.
So, what do you do to help your child with their anxiety?
You walk them through it.
Walking your child through their anxiety means keeping yourself calm while you're at it. If I think of my experiences of supporting my daughter when she is anxious, it takes some doing for me to "sit and stay" in that feeling of my OWN discomfort, let alone hers. I worry about her being anxious - and so I also feel anxious. And that's NOT helpful. So the thing to master in order to be able to "sit and stay" with your child's anxiety is "staying calm when your child can't".
If you can't stay calm, you can't make space to "be with" (sit and stay with) your child's anxiety.
What do you do to be able to stay calm when your child can't?