How to learn black magic to create a font (transfer ligatures from one font to another)?

Question

Fonts

The more I start digging into this topic, the more I become stumped. Everything rests on very esoteric python scripts.
I'm not asking about the creative part, like how to draw your own font. My task is simpler - I want to take one font and add ligatures from another font to it. How to do it?
Found FontForge, it seems to be the most advanced software in this area?
But how to figure out what everything consists of, what to chew? Where are the ligatures? How to get them from one font and reassign them to another? Questions a million, I will be grateful for any relevant information or links.