Time Zone Offset

How do I check if the time zone offset in ConfTool is correct?

You can find many services that show the current time for all international time zones.
An example is:
https://greenwichmeantime.com/time-zone/

Just compare if the displayed time is correct.

You can define the time zone for your conference easily.

Please go to:
Overview => Settings => Main Setup
Please go to the section "Time Zone" and for the option "* Time Zone" choose a city that corresponds with your current time.
For the option "* Time Zone of Your Conference" you can keep the setting "%1" which will automatically insert the official abbreviated time zone name or enter an abbreviation that is more fitting (see image).

Here you can find all official time zone codes.