I'm all about easy, so I know the easy way!
See the flat long slot on the black QD? Unscrew that, but do it over a white paper towel, so you can see the parts. There will be: one spring, one plastic pointed thing, one gasket (which might stick to the slotted top), and the top. Put those four parts together in some oxiclean. Now, unscrew the top of the picnic tap. It comes right off. Now you can run oxiclean, water, and then star-san through it. Put the picnic tap top back on. Then, in reverse order put together the black QD. The "short" plastic pin goes down, with the long side sticking up, then the spring goes over that, then the slotted top with the gasket back in place.
It sounds way more complicated than it is! It's so easy even a Yooper could do it!