THE GMT hand moves at half the speed of the normal hour hand and only goes around ONCE in 24 hours.
If you have trouble setting it here are some procedures to use.
Try this:
Setting the A2836 GMT
If the watch has stopped or is showing the wrong time.( like when you get it)
Give it a swirl or a bit of a wind to get it running,then,
1. Unscrew crown
2. Gently pull out crown and stem to 3rd position (time setting)
3. Turn crown CCW to move main hands FORWARD to desired time. (try not to move hands backwards at any time)
4. Push stem in.
5. Gently pull out crown and stem to 2nd position (date and GMT setting)
6. Turn crown CCW till the GMT hand is where you want. The GMT hand only goes backwards in time so don't worry. There is a detent at each hour that you will see that the GMT hand wants to stay at.
7. Turn the crown CW to set the date.
8. Push in crown and screw down the crown (remember to turn it backwards till you feel the threads match up)
If the watch is running and you want to change the position of the GMT hand but the date is OK
1. Unscrew crown
2. Gently pull out crown and stem
3. Turn crown CCW to set GMT hand where you want.
4. And this is the important one
Turn the crown CW a bit till you see the date shift a tiny bit. ( this ensures the GMT setting gear is disengaged)
5. Push in and screw down crown
If for some reason the GMT is lagging or shows the wrong time for some unknown reason
1. Unscrew crown
2. Gently pull out crown and stem to 3rd position
3. Turn crown CCW to move hands forward through 24 to 48 hrs. and set at correct time
4. Push in crown
5. Gently pull crown and stem out to 2nd position
6. Turn crown CCW to set GMT hand
7. Turn crown CW to set date (even if you have to go through the whole month)
8. Push in and screw down crown.
The bottom line is, the last thing you should do before screwing down crown(besides the backwards turn to line up threads) is to see the date shift a tiny amount.(to make sure the GMT setting gear is disengaged)
I don't know if it makes a difference with the 2836 movement but to be on the safe side, Don't change the date between 9pm and 3am.
Hope this helps. (now you know as much as I do about them)