I can definitely relate to the collection of standards being hard to understand. There are more pieces involved so webmentions themselves are surprisingly simple. But when used together with microformats, the story gets more complicated but complete.

Like on my site, I have a utility to send webmentions to links when I post. But then to receive webmentions, I defer to webmention.io which checks the microformats of pages that mention me. Then I have some JS to query from that service and show them on my page.