Summarize the following:
Put the tray in a dark corner of a shed, closet, basement, or other suitable area. The dark room should be kept between 50 to 70 °F (10 to 21 °C). Because you’re working indoors, the temperature most likely won’t need to be adjusted. For the mushrooms to grow, the temperature needs to be no higher than 70 °F (21 °C) in the daytime and no lower than 50 °F (10 °C) at night. If the temperature goes beyond this, you may need to move the bed to a safer location, such as in shade or indoors.  A dark area, such as in the shade of a tree, also helps, but it’s most important to get the temperature right. You can monitor the soil by placing a soil thermometer in the bed. Mushrooms do well in water, so rain falling on your planting bed is okay. Mushroom spores can be purchased online and may also be found at some gardening stores. Once you have them, put on a pair of rubber gloves. Sprinkle the spores onto the compost, then gently mix them in about 1 in (2.5 cm). Press down on the compost when you’re finished. First, remove the plastic and cardboard if you used it to sterilize the soil. Get some peat moss from a garden center or home improvement store. Spread a 1 in (2.5 cm) layer over the compost. Then spread a single layer of newspaper over the peat moss. Use a spray bottle at least once a day to keep the newspaper wet. If it looks dry, spray it to keep up the humidity level in the bed. Mushrooms thrive in damp environments, so it’s unlikely that you’ll supply too much water by misting. If you’re growing outdoors, increase misting to twice a day to ensure the bed doesn’t dry out.

Summary:
Place the bed in a dark room to grow portobellos indoors. Move the bed to a climate-controlled area for outdoors growing. Mix the mushroom spores into the compost. Cover the compost with peat moss and newspaper. Mist the newspaper daily to keep it moist.