element.innerHTML = -> This document requires 'TrustedHTML'

Question

element.innerHTML = ... is throwing the following error: This document requires 'TrustedHTML'.

I found this documentation about it that I have trouble understanding: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/require-trusted-types-for

How should one go about doing a element.innerHTML = ... with trustedHTML? Do they mean that the snippet below just has to be placed somewhere before element.innerHTML = ...?

const sanitizer = trustedTypes.createPolicy('foo', {
    createHTML: (input) => DOMPurify.sanitize(input)
});

Apologies for being basic here, I just want to understand what I'm getting into.