Guide: Watching the Royal Wedding Saturday
These two links give you the schedule and TV coverage for English speaking countries.
https://www.telegraph.co.uk/news/2018/05/15/time-does-royal-wedding-start-full-schedule-timings-harry-meghans/
https://www.telegraph.co.uk/news/2018/05/15/watch-prince-harry-meghan-markles-royal-wedding-saturday/
The ceremony lasts an hour starting at noon, followed by a half-hour carriage procession. That's 12:00 BST, 7:00 EDT, and 4:00 PDT.
Online, BBC (UK only) and CBC (CA only) are available free. Commercial networks seem to require login.
PBS has a live YouTube stream that seems to worldwide: https://www.youtube.com/watch?v=TDMIcwaFC9o