That's what this is all about! I have always been an outsider to that community and want to find good ways to enter and get involved, but I am also trying to find ways to make ActivityPub based projects more accessible to the average web user.
I've written a lot of intro related pieces which may help you get started: http://boffosocko.com/research/indieweb/. In particular, the second two in the "Introductory Articles" section may be the most useful higher level overviews for you. The wiki has a large number of pages devoted to a WordPress worldview starting here: https://indieweb.org/WordPress.
Along with a plethora of others (who I've always found very warm and welcoming) we're all often hanging out in the IndieWeb chat rooms (there's a specific #WordPress related one as well): https://indieweb.org/discuss. If you want to hop on a conference call, I'm happy to walk you through some of the basics and point you in the direction of areas you're most interested in checking out.
If you're free at the end of June, the IndieWeb Summit is a great place to start as well: https://2018.indieweb.org/. Many of us are planning on attending. If you can't make it in person, we should be livestreaming a lot of it for remote attendees as well.