Hi @Vicky4
Nancy has generously taken time to give you some excellent advice. I also strongly recommend that you NOT use Instant Book. THe mistake I see new hosts often making, is that they assume that Airbnb has somehow vetted guests and that you can depend on ALWAYS getting decent people through Airbnb, and this is definitely not the case. Most guests are fine, but a few are not. Airbnb does not screen guests, and all hosts need to screen their guests, and the best way to learn how to do that is to do it and not use Instant Book, which doesn't allow you to do any screening at all. In fact, although Airbnb pushes Instant Book because it is convenient for guests, I recommend that no hosts use Instant Book. We are private homes, not hotels, and so taking any warm body as a hotel does is not appropriate for private homes.
Really if guests get their account set up properly, and hosts respond to incoming inquiries quickly, it is possible for a guest to get a booking at a listing in as little as 5 to 15 minutes, which is close enough to "instant" for most all needs. I am able to process and accept incoming inquiries/reservation requests quite rapidly (often in 5-15 minutes!!) and so I dont' see why any guest contacting me would even need Instant Book.
Once you get a contact message from a guest, you can click on their name/photo and this takes you to their profile page, where all their reviews will be. THere you can read what other hosts have said about them. Keep in mind many guests are new to Airbnb and will not have any reviews yet. You need to learn how to screen people who have no reviews -- although previous reviews definitely help, dont' just depend on what others have said, as some hosts are not honest and give good reviews to those who they have had problems with. You are going into the property rental business when you sign up to be a host and so you need to learn these skills on screening, and more. See my tips for new hosts here: Tips for New Hosts
You may also want to read this blog on guests to be cautious about: Fifteen Guests You Don't Want