@Deborah321
Deborah I have done a series of 'how to' screenshots to help newer users find their way to various parts of their site.
This one may be helpful to you in setting your preparation time so that you can accept guests leaving and guests arriving on the same day.
The only additional thing you need to set is your checkout time which you find under this same 'Availability' heading by simply scrolling down to 'Check-in/Check-out time'
Just remember to save any changes before you leave each section or your changes will not take place!
To view this image as a full screen item click the small magnifying glass you will see if you 'hover' your cursor in the top right corner of the photo.
Cheers.....Rob