Here's a quick link to the availability calendar for your host location.

For the future, you'll find the quickest way to block out dates where you won't be home or are otherwise unavailable to host guests is to head to the main user dashboard

Once there, find the quick edit buttons for your host locations below your profile photo, and click on the calendar icon

From there, add any dates that you know you can't accept guests. These dates will no longer be available for guests to request.