Family tree guy

Thank you so much. I should have figured that out. Story of my life.

I created the original poster in Adobe Illustrator and then opened the Illustrator file for the poster in Affinity Publisher and saved it as an "afpub" file. The poster is 18 inches high by 26 wide high. I want to decrease or crop the document size to about 16 inches high. I have looked everywhere for instructions on how to change the size of the document. Some instructions refer to the changing the canvas seize under the document menu, but I that option is not there. And the document setup button only allows me to change the document units and dpi, not the inch size of the document.

I opened a document - a family tree poster - created in Illustrator in Affinity. I saved the document as an Affinity image. Now I want to resize the document (or canvas) without changing the size of the photos of relatives in the document. For example, I want to change the size of the image from 20x28 inches to 16 by 24 inches. How do I do this? An option to change the canvas size does not show in the document menu.