Remove your laces from your shoes. Take them off carefully so you do not leave any marks on the shoe holes.
Insert the elastic shoelace into the top two holes and pull them through so the laces are even. Place the laces through the remaining holes in a criss-cross pattern down the shoe.
Thread the laces through the plastic locking mechanism. Pull the locking mechanism up so it is tight on your foot. You should be able to easily slip your foot in the shoe, but it should be harder to get the shoe off.
Cut the ends of the laces with scissors and use a lighter to melt the ends so they don't fray.