Sharepoint Online "Assigned To" Calendar - How to make events assigned to a user show on their Office 365 Calendar?

I want events assigned to a user within a Sharepoint Calendar to then appear on their Office 365 Calendar.

OR

A way to simply let a group of users only view the events assigned to their user account.

How do I achieve this simply?

The preference is for the first so that client devices (in this case most likely Android Tablets) just need to sync via Exchange, no .ics or whatever calendar BS as well.