You have written your book and you want to tell your friends about it. That’s great! You can talk about it on your facebook personal page but how many times can you talk about it? This makes having an author facebook page a good idea.
This page can be dedicated to you the author so you can continuously post about your book, talk about giveaways, book launch, etc.
However, don’t think that a facebook page is a great substitute for a website. With facebook, remember that you are always dependent on an external platform.
Getting likes is only one possible way of setting objectives. You can set different objectives for an advertising campaign. It is best to setup something that drives traffic to your sites, or direct sale or email newsletter signups. If using paid advertising, make sure to target the audience very narrowly, ideally to the people who have interest in that very specific genre.
Also post across groups. Don’t spam groups with your book as that can become a bit annoying and actually prevent people from buying the book. Create posts that are interesting to read and in accordance to the rules of the group, rather than just cutting and pasting links to your book.
Apart from page, consider creating a group. It doesn’t have the same features as a page and will need to be treated differently. But if suitably managed, it can help build long-term relationships with readers and also keep them engaged.
Promotion is not a one-day wonder. It takes a lot of effort. Be in it for long term and work on strategies to direct people to your own platform outside facebook as well. Facebook’s policies keep changing and you might work hard on building a following and then not able to reach it. Building an email list could be life saver.
To understand more about advertising on facebook, go through this link: https://www.facebook.com/business/learn