Add A+ Content to your book's Amazon product page. Use the other Amazon Marketing Resources available to you through KDP.

After your website, your email list is the next most important tool to build for your book’s success and to develop your author platform.

You don’t have to get a website for your book, but you definitely want a web page you own, not a social media page or just a listing

Where are your readers? Amazon affiliate links and other tracking links can help with that question by tracking sales.