Is there a way of using the "Grey" or "invisible" glyphs as a mean for tracing to begin with or to establish the fundamentals

Sorry I’m new to glyphs.
Appreciate any sort of help with this.

Scan a specimen of an old typeface at your scanner’s maximum resolution, set the resolution to 72 DPI, cut it into individual lines, add them to the glyphs as images (Glyph > add image), and trace that.

You should not draw over the apple system font because you would just create a copy of it and you are supposed to draw your own shapes.