How do I set the time zone?

Login to your blog and click Settings.

Scroll down that page and you will see this:

UTC time is set in London, UK. If you are in the UK, you should have a zero in the hours box.

If you are in another country you need to change that number.

For example, if you live in Paris, France your timezone is one hour ahead of UTC so you would put +1

If you live in Boston MA you are 5 hours behind UTC so you would put -5

San Francisco? -8

Auckland NZ? +11

You can find the timezones of many cities here: http://www.timeanddate.com/worldclock

UTC time is on the bottom part of that page - all you need to do is work out the difference.