Hello Carlos,

Thanks for reaching out to us.

Amelia itself doesn't have the timezone settings, it uses the WP timezone settings, that's correct. Here is the basic explanation of time zones in WP -  Time Zones with Amelia

Regarding the timeslots on the front end, here is how it works. This depends on the combination of service duration and employee work hours. That means if the service duration is 1h an employee's work hours are 09 - 17, then the timeslots will be 09 - 10, 10 - 11, 11 - 12, etc.

It is also important to assign employees to the appropriate services, so when the customer chooses the service, Amelia will recognize the employee assigned to that service, and it will display the work hours of that employee. 

I hope it helps. Please, let us know if you have any other questions.