I worked in a commercial mushroom farm producing button mushrooms. The system they used was wheat straw beds about 8" deep laid in wood trays. The beds would be sterilized with steam heat, then inoculated with spawn cultured on grain from sterile tissue taken from inside selected mushrooms.
After the mycelia had properly colonized the beds, they were capped with about 2 cm of well made compost from hot compost piles, made from straw and horse stable manure.
The capping and a change in temperature then would stimulate a massive development of mushrooms, completely crowded from side to side. Successive waves of mushrooms appear until the bed material is exhausted. At times the beds would be watered with a solution of calcium chloride, I’m not sure if that was for the nutritional requirements of the mushrooms, or perhaps mold control or something else.
Oyster mushrooms can be grown in a similar way but on uncapped beds, or in plastic bags or tubes of shredded paper sawdust or straw with holes for the mushrooms to grow from.
It is probably a good practice to arrange for ventilation or filtration to deal with spores, as they can cause lung damage over time.