refining background edge for color change

6 1/2 hours since I first started trying to do this simple thing.  I've watched 4 or 5 videos that went way beyond what I wanted to do, started in different places with 2 layers, or something so that I had to go to another video to try to get to that point.  Not as involved as refining hair, changing the luminoisty of a replaced sky.  I went to the most basic lesson of creating a mask and I don't need to add a kitten from another image.  In all I get to the point of modifying the mask and I'm not in the same place, and can't proceed.  I made an adjustment layer, color balance, when I wiped out the previous attempts and started over.  I created a selection around the objects and inversed and created a color layer and changed that using color from another image that was closer to what I wanted. The masking tutorial went on about why white instead of black, but when I tried to follow this also I didn't see the results and now see that my original layer is gone.  It's not listed as deleted in the history so I just don't know shy I can't do something that is so much simpler than all these videos going into so much more.  I have a wider outline than before and still haven't gotten to the stage of reducing it by refining the mask. I don't get the painting with black, I start and the lighter outline widens.  What am I doing wrong?