Your EnGage network time zone is configured in the Management tab, under Preferences. This is referred to as "Server time". This time zone is used for features such as server logs and scheduling publishes via server time.

Your media players may be installed at different locations across multiple time zones. Your player's local time zone is configured within each players's Site Settings assignment. If you need to create a Site Settings assignment for a particular time zone, to be deployed to a number of media players in bulk, you can do so in the Management tab, under Site.