Hey folks. Struggling to find out how to actually install this. I tried step 1 of the docs, but it fails straight away;

This redirect is not supported by your Home Assistant installation. It needs either the Home Assistant Operating System or Home Assistant Supervised installation method. For more information, see the documentation.

So then I wonder - is this a HACS enabled project? I try add https://github.com/hassio-addons/addon-node-red but it doesn't work either:

The repository does not seem to be a integration, but an add-on repository. HACS does not manage add-ons.

I'm running HA using Docker. I haven't used Node RED before, so wanted to try it out.

Is there any documentation/info on how to install Node RED in Home Assistant when you're not using the above install methods please?