Cutting an image into two / Affinity Publisher V2

[mdesigns]

I am creating a children's book and each page has a full illustration.

My artist provided the images for a spread as a single PNG image - meaning 2 images (meant for 2 pages) on a single png. I want to cut/crop them into 2 separate individual files. How do I do that on Affinity Publisher? I used the crop tool but it's deleting 1 page while deleting the other. I just want a simple cut through the middle.

Thank you

[David in Яuislip]

Here I have an image 800x600
Create a Publisher document 400x600, 2pages, facing pages, start on left
Place image at x=0 y=0
Export using Area = All pages
This will produce two files, left & right

Apologies if this is anto's method, I don't watch videos

[mdesigns]

Thank you all for the fantastic tutorial! Much appreciated.

So, it looks like I can crop into 1/2 within an existing project? My project is a book with illustrations spread across the pages. 

Anyway, I managed to get single files for each page of illustrations from my artist.