First a Softbox, this one is 100cm square, the one I usually use is bigger.
The camera is 1.83mtrs from the subject, this is the distance between my fingertips with arms outstretched. It's a quick and easy consistent measure.
This is the software that I use to generate these images.
6 stages broken down below...
Next add the first backlight from the left, another large soft source.
Then a second identical backlight from the right
Light the background with a couple of Fresnel.
Use large blacks to block the background light from hitting the model.
Add large reflectors either side of camera.
OK, you're finished.