You'd be very surprised at just how well human feces works in compost.
Basically, all you do is buy a bag of your standard compost from Boots
or wherever you get it from, spread some in your garden before laying a
great, big poo on top of it and mixing it together with your hands.

That's something you would do only out of desperation. Human waste is
doubly bad, first because closely related species carry common diseases,
and humans are by definition the most closely related species, and
secondly because humans are carnivores and carnivores concentrate all of
the diseases of the animals that they eat. The second reason is less true
for people than it is for cats because we cook our food, outdoor cats
don't. The rule should be don't use poop from an animal that you wouldn't
eat. We don't eat closely related species like chimps and we don't eat
carnivores or scavengers.