I would like to know how the coordination of signalized intersections is achieved in PTV Vissim?

There are basically two options:

1. For a static offset you may 'shift' all timings of a signal control using the offset attribute in the 'Signal Controller' window.

2. For a variable offset in combination with vehicle actuated controllers you may link two or more controllers using 'Signal Control Communication'. You can link signal controllers which support communication with other control devices.
For additional information please check the PTV Vissim manual 'Linking SC'.