From what I understand, those instructions are for building the release font files right?
I could just open the font files in Glyphs, but the instructions note that it would be reverse engineering the file and data would be lost. Therefore, editing from the source is the best option.
Since I have access to the source, I was trying to see how to use them in Glyphs
Wouldn’t that only open one master? I guess that’s fine if you only want to edit some outlines and then build from the command line.
But if you want to import the entire variable font source from a set of UFOs, you have to open the .designspace file in Glyphs. Glyphs makes this difficult as it doesn’t tell Finder that it can open these files. You have to go to Open With > Other, then switch the filter to All Applications, then choose Glyphs 3. Only follow this approach if you want to save your edits in a new .glyphs (or .glyphspackage) file. Glyphs cannot save your changes back to the designspace+UFO sources.