Copy a old board layout into KiCAD

[der.ule]

@GoldenAge

then how is it specified that the back surface of the board is a layer of unetched copper?

You’ll need to use zones, here is a link to their FAQ:

How to create a power plane (using zones)

This article is about technical aspects of KiCad only, not about using GND or power planes in general. Working With Power Planes In short: KiCad uses zones for planes Zone is a copper area which can have an associated net and which can be filled automatically KiCad doesn’t normally fill isolated areas (and normally you shouldn’t even try that because it’s not electrically good) For a zone to be filled, a pad of the same net must be inside it or connected to it A via triggers filling, too, if…