From my novice point of view, there are a few things that make broad edge calligraphy what it is, especially how they differ from pointed pen calligraphy. It seems to me if you know the syntax, you will get an idea of how it works.
My biggest aha moment about how broad edge calligraphy works came when watching Lloyd Reynolds’ Italic Calligraphy & Handwriting, so you can do that if you only have one minute (skip to the fifth minute). Now if you can spare some moments…
Pen angle: the angle formed by the nib and baseline. Instead of pen pressure in pointed pen calligraphy, we manipulate pen angle to achieve thin and thick strokes with broad edge. In relation to the direction of the stroke, they create the forms in a unique manner. The more parallel the direction with the pen angle, the thinner the stroke formed (and vice versa).
Pen width: the measurement of the tip of the broad edge nib. e.g. A Speedball C2’s pen width is about 3 mm. Pointed pen doesn’t really have this.
Guide ratio: will use pen width as the basis for calculation (topmost featured image). That weird checkered look at the start of a guideline is only relevant in broad edge calligraphy. One black square is representative (and could be actually drawn) of one whole pen width. e.g. In Uncial the ascender : x-height : descender ratio might be 1 : 4 : 1. So with a 3 mm pen width, the guidelines will be 3 mm : 12 mm : 3 mm in each space.
Let me know if this helps!