Cover the pressed bed with a clean plastic sheet. The sheet traps heat and humidity so the bed sits at 30 to 35 °C and 80 to 85 percent relative humidity, the share of moisture the air is holding. Give no ventilation for the first 3 days.
DMR's bed method removes the sheet 7 to 8 days after spawning; its key practice list says 4 to 6 days. Both are DMR, so watch the bed: when white mycelium covers the surface, take the sheet off. Then hold 28 to 32 °C and about 80 percent humidity. Mushrooms start 4 to 5 days after the sheet comes off.