The event will be live streamed, so you can watch it on your tablet, PC, phone or even your TV, if you have a Chromecast at your disposal.
You can find the whole Google I/O schedule here, that would be live streamed along with the other relevant information about them. The opening keynote can be followed live from here.
If you are confused about when the event is scheduled to start, you can find the local start (and end) time here.
Google is also hosting extended I/O events throughout the world where you can watch the event live with your friend, conduct app demos, hackathons and more. You can check if an extended I/O event in your area or not from here and take part in them.