Enter the location’s Time Zone into the entry box or use the Arrow buttons to select the correct zone. The Greenwich Mean Time (GMT) is used as a relative standard (London GMT 0, California - Pacific GMT 8, Thailand GMT -7). For the purposes of this program, hours west of the Prime Meridian are POSITIVE, while those east are NEGATIVE. (12 to -12)
See the manual for suggestions on finding the Time Zone for a new location.