Check the GMT time (
http://wwp.greenwichmeantime.com/ ) and then the market time located to the left of the MT4 display. If the latter time is an hour or two (or more) later than the GMT, insert that difference to the GMT offset as a whole number (e.g., 1, 2, etc.). If it is earlier than the GMT, insert that difference as a negative number (e.g., -1, -2, etc.).