writing tips plsss (I need help [0-0])

I've been planning on writing a book series for a while now(I had the book idea since 6th grade, p.s I'm in 8th grade rn), and I need help in writing it properly. It's a book that uses parables and symbolisms to portray a deep topic that some people refuse to acknowledge. It appears as a simple "fan-fiction" type of book, where there's a character(main protagonist) that is living there everyday life when things start to change. they start dreaming of this weird light in an abyss, days start to repeat, and each day is same yet different. they start to do their best to get out of it, going thru every route possible to escape their non-stop hell. but as soon as they get out of it, something unsettling is revealed. the book basically breaks the fourth wall and involves some disturbingly graphic descriptions. Any tips or advice would help!