These are the changes you need to make on your site to support this plugin.
Configuration
If anything, this plugin will need a fully qualified HTTPS address, so
set the url option accordingly:
url: "https://fully.qualified.doma.in"
Check the rest of the documentation for other options.
Theme
Add the Activity alternate link to your <head>. This will allow other
instances to find the Activity when people searchs your site using the
HTML version.
The Actor will be added to your home page too.
<head>
{% if page.activity %}
<link href="{{ page.activity.url | absolute_url }}" rel="alternate" type="application/activity+json" />
{% endif %}
</head>
Also, add the profile:username, so other instances can find the site’s
profile.
<head>
<meta property="profile:username" content="{{ site.activity_pub_profile }}" />
</head>
And the Actor for website verification.
<head>
{%- if site.actor -%}
<link rel="me" href="{{ site.actor.url | absolute_url }}" />
{%- endif -%}
</head>