Hi Don, you basically want to grab near the corners when you go to drag an image around (images are draggable while you are inside of the Edit > Image command), which will let you drag it by that corner point and then you can snap it on to the corners of other images. Then you do the same kind of thing for dragging a sizing grip as well.
You may find it easier to first draw in some reference geometry like some rectangles and get them arranged first, and then snap the images on to them.
See some of these previous posts for some illustrations:
