You can either do what i do:
Take cas screenshots and edit them together (i use Procreate on my phone/tablet, and ibis paint is a free alternative, but you can use any photo editor)

Or do what Morbid does
Use tray importer to get gallery photos of all households and edit them together

Either way, *do not* create the canvas first, rather import the photos, arrange them by family, then arrange the families and expand the canvas as you go. do not resize sims either. If you want them to be taller or shorter, just use perspective to your advantage, and move them upwards.