Even on my phone I can double tap and change the wall dimensions. I believe it’s in a right click menu on the desktop. It’s definitely missing polish, a UI designer, and any kind of logic on where stuff should be located. It is actually usable to map out a house to figure out furniture and basic stuff. Drives me crazy that I can’t figure out how to do mechanicals in it though.
Double clicking on the wall opens a dialog to type in dimensions.