Write a bestseller book

i’ve always wanted to write a book but i never know what to write about!!Maybe about my life but that could be boring or how about somebody else’s life (invented person) but i don’t know where to start sooo i hope one day that “thing” will come true (i really do hope)!!!^_

i want to write a book, i just don’t know where to start…. plus i’m the worst writer in the universe. and to top it off i can’t seem to get my thoughts together, they keep jumping from one thing to another…

I know I can write a book.But I wont write any untill Im sure that I can write something history making and record breaking