Using a pair of scissors, carefully cut along the top edge of the mushroom grow kit bag, ensuring no damage to the substrate inside. Make a clean, straight cut across the entire width of the bag, allowing easy access to the substrate and mushrooms as they grow. Be cautious to avoid cutting too deeply into the substrate, as this could disrupt the growing environment. Once the bag is cut open, proceed to follow the instructions for the subsequent steps to cultivate your mushrooms successfully.