Click on the icon for the club whose fixture you wish to download. Your web browser will then begin downloading the calendar file to your computer.
NB: If you're using an iOS device, you will need to do this in the Safari browser - it is the only iOS browser that supports calendar importing.
Option 2 - Subscribing:
You can alternatively subscribe to any of the calendars listed. If you subscribe, you have the added advantage of always having the most up-to-date fixtures in your calendar program, even if changes are made during the season (which they quite often are).
Simply right click on the calendar you would like to subscribe to, choose "Copy Link Address" or a similar option, and paste the address into your subscription-enabled calendar program (such as Google Calendar).
Compatibility:
All calendar files are in .ics (iCalendar) format. The ICS format is compatible with common calendar programs such as iCal, Microsoft Outlook and Google Calendar.
For a full list of compatible programs, click here.