how do I find the files I migrated into the Mac, and then transfer the photos to another user on the same MacBook Air??

While I've never used Migration Assistant from a Windows PC, I imagine that the folder hierarchy would remain intact. Try the following search from Finder to locate:

You can grant the other user access to the folder(s) using Get Info (unlock with Admin credentials to add):

In Finder in the left col. click on pictures and look for the Photo Library folder. Copy this folder and then in the other user paste that in that Pictures.