Subscribe in Google Calendar via email@example.com. This may not include one-off windows. If there are differences, then the wiki page is canonical and correct.
Cadence: MediaWiki follows a weekly deploy cadence known as the Deployment Train, except for backports. For other services, teams decide their own schedule.
Schedule: Generally use Backport windows instead of scheduling new windows. But, long running tasks and others things covered by Inclusion criteria do require their own windows. When creating windows, schedule more time than you think you need, to account for issues that might slow you down. One hour is best for most things.
Times are pinned to San Francisco, and thus the UTC time changes in March and November due to the DST.
Communicating: Deployments of new or major features should be announced on the Wikimedia blog, Tech News, and/or global MassMessage to relevant communities. Changes that are likely to affect cache behaviour, add new cookies, or utilize new database tables, should be announced on the ops mailing list first.