The time on a sign is obtained automatically from the GPS signal in the sign controller and cannot be set manually.

NOTE: the time factor is obtained from the sign and displayed in DS-Live™ every 20 minutes.  So it is normal for the time to be out (behind) by up to 20 minutes.  If the time is out by more than 20 minutes then you need to check the steps below and take the appropriate action.
If the time on your sign is incorrect, it is very likely the sign is set to the wrong region (eg. VIC or QLD) or the GPS process has failed and the sign needs to be restarted.  

If the sign is set to the wrong region, log into DS-Live™ and from the Sign List tab click on More Info for that sign.  Select the correct region and click on "Change".

If the region is correct, then restart the sign by pull the main equipment fuse in the control box, wait 10 seconds and then insert the fuse again.

After restarting, give it 10 - 15 minutes to re-connect with the GPS and it should have the right time.