Exporting your Outlook (Desktop) Calendar is easy!
Step 1: Open Outlook on your desktop
Step 2: Select the calendar you want to export.
Step 3: Click File > Save Calendar
Step 4: Name your iCal file.
Step 5: Optional: Click "More Options" to specify a date range
Step 6: Optional: Click "Detail" to choose the amount of detail you want to show.
Step 7: Save
NOTE: Depending on the size of your calendar, this may take several seconds, or a even a few minutes to run. Please be patient while it generates the files. Upload this iCal file and we'll get busy importing all your past and future appointments into Gazelle.
For more info visit this online resource to transfer your Outlook Calendar to Google Calendar and then your Google Calendar to Gazelle. Both approaches work.