Yep, an issue with the anchor links that'll be updated soon. It's supposed to just link to a lower part of the page.
If you scroll down you'll see a top-level header also titled "Configure Zipkin tracers" that describes how to configure the Brave tracer. You don't really need to do anything special here - just point your Zipkin tracers at the Stackdriver Zipkin Collector rather than your existing one.
It doesn't show zipkin configuration :)