Do you want to create your own Fediverse instances?
MANAGED HOSTING
By far the easiest way is to use a managed hosting service such as:
https://federation.spacebear.ee
https://cloud68.co/instances.html
https://masto.host
https://writefreely.host
The hosting service does the tech stuff, but you own and run the instance.
DO IT ALL YOURSELF
Alternatively, you can do all the tech stuff yourself. This requires a lot more skill, but it gives you a lot more flexibility with choosing software.
YUNOHOST
Halfway between these two extremes is @yunohost, server software which lets you install your own online services extremely easily:
Once Yunohost is installed on a server, you can add and remove services yourself through a graphical interface.
Fediverse services include:
CastoPod
Friendica
FunkWhale
Glitch-Soc
Mobilizon
OwnCast
PeerTube
PixelFed
WordPress
WriteFreely
There are also many, many other services:
Yes, you can add ActivityPub support to WordPress with this plugin:
https://wordpress.org/plugins/activitypub/
The developer is @pfefferle