Microsoft should be able to detect your time zone automatically when you use a Windows machine. But occasionally you may need to change it.
To do so, click on the date and time statistics in the bottom right-hand corner of the screen. Then, click on the “change your date and time settings” link.
There, a window will show you the date and time, along with the ability to change your time zone. Press the appropriate button, then follow the prompts, and you’ll be able to change your time zone.