The easiest way to perform a synchronization between multiple devices is using the same sync-account for sync. 

To sync your calendars you add such an account in the Android system settings of your device (normally under →  Accounts and Sync), as most of the devices rely on Android sync functions. If you, however, use Microsoft Pro Sync or are on a device like for example Huawei devices without Google services, you do it in BC → Calendars & Task lists. All necessary details can be found here.

Hint 1: While adding the account to your Android device, please make sure that you set a checkmark behind → Sync calendar.

Hint 2: If you want to view the → Birthdays on various devices, please make sure that you set a checkmark behind → Sync contacts in the list. The birthday information is read out from your contacts based on the contacts permission your grant.

When it comes to sync of task lists across various devices, you need to make sure the same account is added as well. Please find more detailed information here.

Hint 2: Please note, that the series and priorities are not recognized by Google/Microsoft and therefore may not be synced fully. You can, however, manually back the categories up with the import/export task lists feature. You will find it in the → settings under → maintenance.

After a short first synchronization everything should be available on all devices, if they have a consistent internet connection. If you set up the devices correctly and still have sync issues, you can resolve them here.