You can use the forward and back buttons at the top of the calendar to navigate back into the past or forward into the future.
Week view / Day view:
Week view shows you 7 days of activities at a time, while day view shows a single day.
Go to today:
The Today button takes you to today.
Items in your calendar:
Begin / end harvest markers
Click on any item to explore its details.
Note that the first time you navigate to a month it will need to load from the server, which can take some time depending on your internet connection speed and the number of activities in the month.