Start with clean, dry, fully brushed hair
Apply a heat protectant
Plug in the flat iron and set it to a suitable temperature
Divide hair into small sections
Clamp a section near the roots
Rotate the flat iron away from your face or toward your face, depending on the curl direction you want
Slowly glide the flat iron down the hair while maintaining the twist
Release the section gently
Let the curl cool in your hand or pin it up if you want more hold
Repeat on all sections
Finish with hairspray or a light styling product
Avoid touching the curls until they are fully cooled