I think you're doing just fine.
The problem is following a badly written tutorial.
It says to create a 'New' document of width 1400px and then to fit an image 2816px wide into it and expect it to fit....yeah right.
So you've done nothing wrong, except believe everything you read.
You have two choices though:
A. Transform the image to fit the document.
B. Create a document the same size as the image.
I haven't looked at the other image you need to use so they may define which you do but I'd be inclined to transform that image to fit the document....and here is how:
With the 'Upper Mountain' layer selected hit Ctrl + T on your keyboard.
This puts you into 'transform' mode and displays the 'bounding' box with small squares locate din the corners and at each edge midpoint.
Note it extends beyond the document...but don't worry about that.
(Turning 'snaps' on will make the next bits easier)
Click and drag within the bounding box to move the image so the top left corner snaps into the boundary of the document. (Be care ful NOT to drag the very centre....its the pivot point for rotation.)
Hold SHIFT, (to constrain proportions), and click and drag the bottom right corner of the transform bounding box (the small square in the corner) up and left until the edge of the bounding box is aligned with the edge of the document.
You may want to zoom in closer to make sure you align it correctly....snaps don't work in this situation)
Click the 'tick' in the menu bar to accept these changes.
The image should now be the same width as the document with the grey background in the lower half.
Hopefully the rest of the images are the right size but if not then just transform them in the same way.
If you make a mistake DO NOT transform again until you have UNDONE your previous mistake, (Ctrl + Alt + Z)....transforming reduces image 'quality' so should only be done once.....and preferably only ever to a smaller size.
Regards.
MrToM.
@
gedstar
PS...Not you as well!....sheeeesh!
Are you taking lessons from Sam?