In Teambook, the concept of Time zones is important for organizations with resources scattered around different... time zones ;-) ! 

In the situation when a planner specifies a start time for a booking related to a certain user, Teambook will take this users' time zone into account and make sure the booked timeslots are synchronized accordingly in her/his calendar. 

Note that the time zone can be set at Organization level (and thus will be the default value for all users): 

and also in each User's master data, if this person works on a specific time-zone, different from the company account settings: