Clicking the "Subscribe" button will trigger iCal on your computer to enter a new subscription to your calendar. iCal will prompt you to enter a account name and password for the FileMaker file.
Click the "Send Links" button to create an outgoing email that you can send to anyone you want to share your published calendar with. The email will contain two links: a "webcal" link that will work with any Apple product, and an "http" link that some other devices may require.
You can also use this button to send an email to yourself to subscribe to a calendar on your iPhone or iPad.
Google needs a different URL format--our "private url". Learn more here.
If you have multiple devices linked to an iCloud account, you might want to first subscribe to a calendar on your Mac, because you'll have the option of choosing "iCloud" (as opposed to "On My Mac") when you add the calendar. Then that calendar will automatically be pushed to your other devices. You'll still have to enter the username and password for that calendar on each device, but it will save you a few taps.