CatchApp for iPhone
Go to the Home tab in the app and click on the 'Settings' button, located on the bottom left of the screen;
Click on 'Manage Calendars';
Select either Apple Calendar (iCal) or Google Calendar (GCal), depending on which you would like to sync with CatchApp.
CatchApp for Outlook Email
Open CatchApp and create a new invite in order to open the Calendar page.
Click on 'Sync Calendar' in the bottom left of the Calendar page.
Enter your Outlook Calendar username and password to access your events.
That's it. Just follow these instructions and you'll be set up in no time.