Overlay a photo on another?

Thanks for your help!

I guess that was not my only "problem".  I followed your instructions and now have the image over the background.  However, I had used one of the available tools to "remove" unwanted elements leaving just the subjects.  The area that used to have unwanted elements is white and it was my understanding that the unwanted  section would become transparent when placed over the background.  This is not the case.

I now have the entire modified image sitting on the background.  As usual. I am not sure what do do next.

When I select my image and press Ctrl-J, I get my image outlined with a checkerboard rather than the part I want to omit which stays white.  How do I achieve what you did in your example.  I.e.:  Everything around the climber is checker board.  I have tried this over and over, always with the same result.

Again, thanks for your patience and your help.

I did use the selection tool to outline a group of people.  Nevertheless, the group profile comes up with a checkerboard and the part I do not want does not.  In your example the climber was selected but it was the background around him that was checkered...

Your latest comment caused me to look more closely.  There were no marching ants along the bottom of my grouping.  Though I had some problems defining what the selection tool was to select, I have now accomplished my simple goal and I very much appreciate your help!