With most types of insulation, it doesn't really matter which way it's installed. However, there are a few exceptions. For example, if you're using fiberglass insulation, it's important to make sure the fibers are facing the right way - if they're facing inwards, they'll trap moisture and could eventually cause mold growth. With most types of insulation, though, it doesn't really matter which way it goes - as long as you make sure all the gaps and holes are sealed up properly. You might want to consult with a professional to make sure your home is properly insulated.

Installing insulation generally doesn't require a professional, but it may depend on your climate and the type of insulation you're using. There are many resources online that can help you install insulation correctly, depending on your specific situation. Generally speaking, though, it is best to insulate walls and ceilings in a home so that the warm air stays inside during winter and the cool air stays inside during summer. This helps keep your home comfortable and energy-efficient year-round.