Printing from Layout - print area outside white rectangle

I am can manage SketchUp fairly well but am just starting with Layout. I have inserted my SketchUp file into Layout and want to print a plan view of one room of the house. I am using an A3 printer in landscape. When I put the scene I want to print in the middle of the white rectangle that I assume represents the paper then print, I only see a corner of my plan. To see all of it, I have to place part of the plan outside the white rectangle. What am I doing wrong?

Probably you need to adjust the scale of the viewport so it’ll all fit on the page. If you share the LayOut file I can show you how to fix it.