Houby hunting, then PF Tek.

Obviously, do lots of research. There aren't many deadly varieties by some of them look very similar to edible ones.

I wonder how many trial and error and generations of humans it took to realize which mushrooms were safe to eat. It's fascinating stuff.

Look for ones that turn blue when bruised.

Also, the fundamental methodology is to start with an extremely small amount. If there are no observable effects after some hours, eat double the amount. And repeat until there are clear effects, and decide if it's something useful. For food, for fun, or to use for poisoning enemies.

There are many species that contain psilocybin. I don't know China at all, but I'd be surprised if some weren't endemic. So you'd need to do some research. I my experience, they tend to grow on cow shit. And they're somewhat unusual, in that they turn blue when bruised.

In Indonesia they're legal, you can buy mushroom shakes at the beach. In general there are endemic psilocybin mushrooms most everywhere, though it might be illegal just to pick them, like in my home country Norway.