The first and most important step in preventing rainwater from damaging your home is regular gutter maintenance. You should regularly remove stones, leaves, and other debris from the gutter drainage system to improve its efficiency and effectiveness. Removing twigs and leaves also prevents pests and animals from forming a nest, which could block the drainage system. Adjusting gutter accessories helps prevent leaks and reduces noise from gutters and downspouts.
Screw the white sheet through the overlapping sections. Or if you want something more elegant, a pop-shaped rivet (according to my comment). There are several upgrades you can purchase for your gutter system, including gutter downspouts to reduce the amount of time you spend on clean and maintain them.