Bob,
Only just notice your post.
Footprint on mine is about 18" wide x 17.5 inc deep (inc overhang parts).
I have my PSU in a ventilated box 7" x 9.5"
However my build was on a desk 5ft x 2.5 ft, which I found useful for tools, the build manual, elbow room etc. Computer & monitor to one side, so not on that desk.
Also to consider
electronics (if separate)
computer - if you're using say a laptop
room for tools
room for filament
trailing cabling between electronics (if separate) & the printer
In the build I also found it useful to tip the printer up & forward to get access to the underside, there was a wall behind so couldn't fall of the edge.
Other builders may have done it in a smaller space of course, but if I was doing it
again I would still be looking for that 5ft x 2.5ft build area.
Mike