I must say that you need to read the very detailed help file that comes with the software... but to help..

Use the selection tool to select the object you want to cut out of photo 1.
Ctrl-C to copy the selection
Go to Photo 2 and then Ctrl-V to paste selection or Ctrl-L to paste as new layer.
You can now move the new selection around in the new image.

This is just the simplest way but not the best way.. extraction is a huge complex process that includes masks and other advanced topics.. Good Luck1