how to do this

[defaultthy359c4215o]

 Try to have this effect but I can't
Can you help me ?

Can you help me ?

[Derek Cross]

You need to cut the girl out from her background to isolate her,  maybe using Select > Subject, then adding in a background and possibly using a gradient to gradually blur the background as it recedes and merging in a cloud effect. Also adding some reflection from her feet.

It will take some skill, if you don't know how to do it, consider a Photoshop compositing tutorial from LinkedIn Learning, you can get 30-days free

 access.