@Melanie802 With only one rental a simple Excel spreadsheet may be all that you need. I recommend that you talk to your tax accountant about what expenses to track and how to record your reservations.
I have had multiple rental properties over the years and a spreadsheet listing reservations, their dates, what the guest paid, what taxes were collected as well as another spreadsheet tracking utility costs, maintenance and other topics found on Schedules C or E very helpful in reporting property income.