How do I setup presence using Homekit and Homebridge?

I can only recommend to read this thread here:

There are also instructions on top.

The Homebridge MakerAPI integration reduces a lot of overhead on the hub site and is in my opinion much more reliable. But I am biased here a bit.... I wrote that plugin.

Also, I am not sure if you are running on a Rasberry PI, but I had one use who tried HOOBS (https://hoobs.org/) and said it was very easy to get running.