How to arrange the lighting to take such a photo? Do you need a flash? The more detailed the explanation, the better.

It's so late, I have no energy to write you a long speech. Say a few words briefly.

It is not difficult to exclude such photos.

First of all, try to use large aperture fixed-focus portraits, such as Canon EF50 1.2L or 1.4. Shoot with aperture 1.4, Av mode, aperture first.

The shooting site should be well lit. Pay attention to the little model, the main light comes from his left front. But other places are very bright.

Fill the soft light in the right front of the model with a reflector.

The camera can turn on the external flash and use the soft light board to understand the skin color of the small model, further beautify the skin and make the skin whiter.

You can set automatic white balance. According to the needs of film production, it can be set to a slightly warmer color.

After shooting, use PS to properly enhance the curve, do color filtering, and blur appropriately.

By doing the above, you can take similar photos.

I hope my answer can help you.