@Shreya2711 I'll be frank with you: I only managed to read one chapter because I could barely understand what you wrote.
I realize that some authors aren't native English speakers, so I won't bash you too hard. Here are some of the stuff that needs fixing:
The sentences are dry. In fact, the first three sentences are all about the same length. Try to vary them, and use more transition phrases to make everything flow more smoothly. Also, your descriptions are quite lacking. Here's a sentence you wrote: "...a sound as if someone was carefully taking steps." If you wanted an air of suspense, another way to write it would be: "...a sound as if a creature were prowling in the night." It might not fit too much with the context, but I hope you get my point. As Mark Twain once said, "The difference between the right word and the almost right word is the difference between lightning and lightning bug."
Grammar errors. There many places where you missed particles and other things that made the paragraphs confusing. Use Grammarly as a grammar-checking software, and use other websites to study grammar in general.
The paragraphs are humongous. Even I tend to make large paragraphs, but yours are just straight-up huge. Split them up for important plot beats, and make sure to put dialogue on a new paragraph as well. If you aren't sure how to format and punctuate dialogue, there are plenty of websites for reference.
Read more books. A big issue among new writers is that they don't read too many books, and that makes it difficult for them to replicate the proper format. I'm not accusing you of not reading, but it's just a suggestion in case you're not an avid reader.
That's about it. Sorry that I couldn't critique your plot because I just couldn't keep reading after the first chapter. Writing prose is something that can only improve through constant practice and effort, so as long as you keep on writing, you'll get better eventually.