When hanging blackout linings, the most effective way is to ensure that the blackout side faces the window. This is done to maximize the lining's light-blocking capabilities. The blackout side is typically the side that is more matte or has a slightly rubbery texture. It's designed to block out as much sunlight and heat as possible, making it ideal for bedrooms, home cinemas, or any other space where you want to control the light levels. Once the lining is properly installed, it should completely cover the window to effectively block out light. Remember to measure your window correctly to get the right size of blackout lining.