New answers tagged software
If you find the various software intimidating/hard to get started with/has a steep learning curve there is always graph paper (or a scale ruler), cardboard and hot glue to make a physical model (and possibly a camera, if that helps you "see" better than looking at the model directly - people vary.)
I've had good luck with SweetHome 3D. I like it above Sketchup for this kind of thing because it's much easier to adjust things, say move a wall 2". It's also fast and fairly customizable.
Try Blophome. I've been using it for years. It's very simple and you can add lights and regulate the ambient light of the project. It has a large amount of furniture.
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