The first time that you start SmartDay Mac, it syncs automatically with iCal on your Mac.  Here are a few things to know:

Sync is automatic

Your iCal calendar always syncs with SmartDay Mac.

Sync is refreshed automatically

Each time your iCal calendar refreshes its calendars, it then syncs with SmartDay. To change the refresh rate, in iCal go to Preferences -> Accounts -> Refresh calendars.

Sync speed depends on data size

If your iCal calendar has a lot of data, it can take a long time to sync with SmartDay.  You can adjust this by decreasing the refresh rate (see above), and also by choosing to sync a smaller date window. In SmartDay, just go to Preferences -> Sync to adjust.

Reminders are Tasks

SmartDay syncs its tasks to iCal as “Reminders”. There are a few things to be aware of, as explained below.

Syncing from SmartDay to iCal

If you create a new calendar category in SmartDay, you can sync both Tasks and Events across to iCal. This will create new calendars in iCal.

Important: If you want to sync Reminders to and from iCal, you can only do this by first creating a new calendar category in SmartDay. See below.

If you delete a calendar category in SmartDay (that you had created in SmartDay), it will also delete that calendar category and all of its Events and Reminders, in iCal.

Syncing from iCal to SmartDay

Because of the way that iCal is set up, if you create a calendar in iCal then sync it to SmartDay, you will see both Events and Reminders from that iCal calendar, in SmartDay. And you can create new Events in that calendar from within SmartDay and sync them back to iCal. But you cannot create Tasks in that calendar in SmartDay, and sync them back to iCal. The only way to sync SmartDay tasks back to iCal is to first create a calendar category in SmartDay.