If I remember correctly button mushrooms are secondary composers.
So they would grow on your finished
compost and or aged animal manure.
Right now I have started a button mushroom kit that looks like gray cobwebs on straw and black compost that needs some added water and gets put on top.
The mycelium has grown through the compost and looks white against the black. I expect pins in about a week.
When the kit is finished I will mix it with finished compost in the garden.
A friends dad got a permanent button mushroom colony established near his compost heap in this way.
No, it will not take over the whole garden as there are other interested parties that will make sure it will stay in it's ideal niche if at all - there is constant war going on out there and your role is to play faith for trillions of organisms.