Help with making an mcreator plugin (Goldorion)

Explain me like a 5 years old, freemaker
I want to make mcreator plugin but some said it requires free maker knowledge then i came across the legend Goldorion's Plugin maker, i said: Yes! Finnaly! no Freemaker but it took me 5 minutes of opening it to realise not, anyway, i started learning freemaker but up until this moment i still have no idea how is it related to mcreator so if the all mighty Goldorion would help me to understand his plugin, i'd be pleased!