So, this is my effort for the Photoshop "learning layers" exercise. I cannot, for the life of me, figure out how to blend this any better. But at least I got two layers figured out and put the two halves of the island together. See the white line and the smudges where I tried the suggested eraser? Eeek! See... I told you it would look like amateur hour around here for a while. :) Oh, well... at least I am learning something. Thanks, 365!
PS... Comment only if you care to, no need otherwise. This is me, on a journey, so feel free to take a pass. If I don't post these, I may have nothing else to show for my day.
10/1/2020: Finished year 7 (!), with continuing gratitude towards this amazing community. Based in St. Louis, MO. Regular worker-bee and self-taught photography dilettante....
The fact you figured out how to create a larger canvas and a second layer with a duplicate of the original photo that you then flipped horizontally is a start to the Photoshop learning. By posting this picture, you have something that will prove just how much you've learned a few months down the road.
Rosie, this is what I did. I hid the layer below and clicked on the the layer with the horizontally flipped photo, then I used the eraser and "nibbled" some of the photo in the center where the two would meet. The "nibble" was uneven, not in the same line. I used a feathered eraser, I believe. Then I pulled the photo in this layer over a little to the right so the two photos would overlap. When I unhid the lower layer the seam was smoothed. Hope that helps.