If you are still struggling, here is the process I adopted.
You do need an image with an all-over plain colour or texture, this becomes background and the wide border, white on my image.
Set the page size and orientation.
Place this plain image in the queue sized "fit to page" with the crop scissors on.
Set the page to Freehand mode with the 'F' icon on the preview.
Make sure nothing is selected in the thumbs and page preview.
Open Print Properties with a 2 second right click.
Set the print size for the main image.
Drag the main image to the page preview and position approximately.
Open the page editor and use the Size/Position tab to set the position accurately; enter the dimensions to the page edge directly for the best accuracy.
You may need to use right click and "send to back" on the background image.
Select the background image and create border(s).
Select the main image and create border(s)
Create text and position it.
Done
Terry