Thanks BW, I already have added shadows just the way you indicate
But to make you happy, I've put just a little bit more.
The street light seems rather dim, so the shadows would not be too contrasted.

Maybe I said that wrong. I meant some dark color where your subjects touch the ground. Here, I made a gif, using the boy's feet to show you what I mean. https://i.imgur.com/2tfukZe.gif

I used black in this gif, but it's probably best to sample a dark color by the boy's feet using the eye dropper. You can then use PS's Color Picker to make that sampled color lighter or darker. I used a 33% opacity brush, but went over it a couple times or so. IMO he looks more "attached" to the ground now.

Thanks for your gif, for your time, for your interest! I understand what you mean better now.

YW author. They do look better now. They don't look like they are floating in the air. I got some more suggestions if you would like to hear.

That's intriguing BW, more suggestions? Yes please!

Thanks BigWaveRider, he he now I now what your initials stand for! I don't think it is against the rules to tell settings, on the contrary we are asked to help and give tips to eachother.
The tone balance you did is much warmer. Usualy I do warmer pics but in this case I chose to keep it in colder tones. I like them both, now I'm confused

I added my settings for you in the Imgur album. Yea it's more warm for sure. At first I tried a warming color filter but it was inadequate. Up to you which one you like.

https://imgur.com/a/fBQpN

Haha. Yup, BWR = BigWaveRider . Gonna be changing my name soon. Mods said they can't give me a name change, so I have to make a whole new account.

Lolu!!! so good to hear from you! I've already changed the direction of the eyes of the little girl from the source image. It is something to get balanced between her position, the position of her head and what she is looking at...