The photographer came in and customized white balance shooting with Canon 650D plus 200 flash unit and 2-in-1 1 focusing board. How to shoot this effect? thank you

Enlarge the board at 45 below, and then put the pants on it with the legs down. The lamp is placed in the corner of the high end, making an angle of 60 with the diagonal direction of the board. Be soft, not direct.

As for the angle and texture of light and shadow, it depends on the brightness and color temperature of your lamp.