To change which calendars you're sharing or using for your availability:

1. Head to the calendar by tapping on the calendar icon (🗓️) at the bottom of the screen.
2. Tap the options icon to the left of the month. This will open a menu with two tabs: ‘View’ and ‘Share’. The ‘View’ tab controls what you see on your calendar, while the ‘Share’ tab controls what your friends see when viewing your calendar and / or availability.
3. Switch to the ‘Share’ tab.
4. Your Howbout calendar is shared / used for your availability by default, but if you want to share an external calendar (or use it for your availability) as well, turn it on here. Note that any calendars that aren't turned on will not be visible to your friends and won’t update your availability, even if they show on your calendar.
5. Scroll down until you see a list of your friends. If you’re sharing your ‘Calendar’ with a friend, they can view your Howbout calendar and any external calendars you’re sharing. If you’re sharing your ‘Availability’, they can check if you’re busy at a certain time / day but can’t turn on your calendar or see any of the details.