The first choice to make before starting to write is the tool to use. That can be paper with pencil, ballpoint or fountain pen, a typewriter or a computer/laptop with a text or word processor.
We don't recommend using a tablet or phone with only a touch screen for typing a story or poem, let alone a whole book.
If you plan to use a computer, don't forget to make regular backups. It would be painful if you lost your book due to a hardware failure or ransomware when it's nearly finished.
Actually, i like to write stories and poems. So i want to start writing a book. But I donty know how to start? If someone knmow the process then let me know.