If you are asking about when the scheduled tourneys are:
https://support.chess.com/customer/en/portal/articles/1444927-how-do-live-tournaments-work-where-can-i-join-one-
Schedule is at the bottom.
For something like Arena Kings,
https://www.google.com/amp/s/www.chess.com/amp/news/arena-kings-chess-returns-for-season-3
Is there any threads where I can find schedule of al BIg Events that are held in Live chess?
For example, there is Big Event 3+2