Summarize:

Ensure that there's nothing in the oven, and turn the heat on. While the oven heats, you can measure out your ingredients and begin to prepare the dish. Be patient while the oven heats up. Depending on what kind of oven you have, it may take some time to reach the right temperature. Most ovens will make a noise when they've reached the correct temperature. To make the cheese bubbly, carefully pull the foil off of the dish. Leave it in the oven on the same temperature for an additional 10 minutes, or until the cheese starts to bubble around the edges. If you like crispier cheese, leave the uncovered dish in the oven for 12-13 minutes. Let the dish cool for 5 minutes, and then use a spoon or spatula to remove a portion from the dish. You can sprinkle additional cheese across the tortellini to make it even cheesier! If you have leftover tortellini, scoop it into an airtight container and store it in the refrigerator for 1 week to enjoy the left overs.
Preheat the oven to 350F (177C). Remove the foil and bake the dish for 10 additional minutes. Scoop the tortellini out of the dish to serve.