I’m confused about notifying Google

I installed an activated this plugin since I read that that’s all you had to do to get it working. Looking at the Settings page, I see “Search engines haven’t been notified yet. Write a post to let them know about your sitemap.” so apparently there IS more than what was suggested.

I don’t have posts on my site, just static pages. Where is this post supposed to go?

When I go to the Google Search Console to verify, I’m instructed to download a google*.html file. Is this something I need in addition to your plugin?

Please clarify.