Here's how achieve your curls using a flat iron. 1. Brush your hair and spray on heat protect product while waiting for the flat iron to warm up. 2. Part your hair into sections. Again, spray on some heat protect before you start curling. Start curling the hair sections by turning the iron slowly. The volume of the curls will depend on your taste. 3. Curl the rest of your hair and then spritz on some hair spray when done for more long lasting curls.