Mushrooms usually need some kind of substrate to grow on. Some yummy organic matter they can break down into food. Straw works really well!
If you don’t have easy access to cut logs or wielding a chain saw is not your thing then straw inoculation might be your best way to get into mushroom cultivation.
Certain mushrooms species will “clean” the straw of any pesticides that were sprayed on it breaking them down into hydrogen and carbon that can safely be returned to your garden soil. The mushrooms you eat will contain no trace of these toxins.
This is a low-tech, no waste, regenerative way to grow mushrooms and easy enough to do at home.