How to cut out an imagine and post it on another photo in Gimp?

[Time Of The Season]

I have this photo form the 70s. It's my dad with his brothers. He posted it on his FB and I liked it. I wanna put animal faces on their faces, and post it as my Twitter background. You know, just post animal faces. Not blend them in and stuff.

This might sound astonishing, but I'm 15 and have never used photo shop or Gimp.

I just downloaded Gimp, since it's free, AND IT'S SO CONFUSING. I literally don't understand anything!!
I have that Animal Faces app on iTune, but I don't know if I can use the app on my laptop. I could only use a portion of the photo on my phone. I have an HP, not a Macbook.

[　☥♡☮　]

Before you do edit, you may have to consider use of others photo, and to manipulate, even though as joke humor, may not be condoned by parent, worse by placing on web, undoable,

With gimp you can drag and drop whole image into window,
Or copy and paste, if you only want part copied, you selct with lasso tool, copy , then paste over other image,

There may be other steps like layer attributes to add alpha channel, or add as new layer, you can right click layer or from menu, or tabs

http://docs.gimp.org/2.8/en/
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