Know only things to be dangerous in OpenSCAD – Cubehero Blog (2013)

That's one of the coolest tutorials I've ever seen, just from a pure formatting and writing perspective.

I'd still recommend FreeCAD if you actually want a CAD rather than a tool to record a design you made yourself with very little Computer Aid, but if I ever have a use case for FreeCAD this will probably be where I go for a refresher.