There are three settings to consider when setting up your Events Calendar.
General allows you to add Friday and Saturday sunset times to your calendar. These times will be based on the time zone setting (Admin Settings / Localization) and may not be to the minute of your exact location.
A minimum of one category is required.
Each Category needs a name. You may choose a different color for each category. Darker colors display better.
Categories can be used to filter the calendar display so that a single category of event can be displayed without the clutter of other categories of events.
If you should discover you need a new category while adding an event, it can be added on the fly without the need to exit the adding process.
External allows you to sync an iCal friendly, public calendar with your SimpleUpdates calendar. Just add the link.