The answer to 'how to kill bed bugs' is to use a combination of professional extermination and thorough cleaning and preparation of your home. Bed bugs are difficult to eliminate on your own, so it's best to work with a licensed pest control professional who can properly identify the infestation and use the right treatments.
The professional exterminator will likely use a combination of pesticide sprays, heat treatments, and other methods to kill the bed bugs and their eggs. They will also provide guidance on how to prepare your home by washing and drying all bedding, clothing, and other items on high heat, vacuuming thoroughly, and eliminating clutter where bed bugs can hide.