Transition from my old HTML website to my new WP website

I have a question. I own a domain where I have a simple website (in HTML). I would like to create completely new website, this time in WordPress… but I dont want it to be visible until it is completely done. So what is the best solution for this? Do I have to install WordPress in a some subdirectory and them move it to the root directory and replace my old website like so? Or what is the best way for this situation?