struggling writng

ive been trying to get back into writing my "book" again with some new ideas and its been made painfully clear that i dont have a damn clue whats going on in the world im making

how the HELL am i going to write a story where a wizard born from a once prosperous nation now in ruins somehow discovers alternate timelines and loses everyone close to them and defeats god before realizing this is only the beginning

WHAT AM I DOING AND HOW DO I MAKE IT MAKE SENSE