With the clock.
Make sure your PC has the correct time showing at the bottom RHS corner.
This affects the time left, shown on the BetTrader.
The correct time can be easily obtained from ones mobile phone.

Quit often Betfair cant be bothered adjusting any ammended start times , especially when it comes to races in the USA .
There is nothing one can do about that.

Cheers.

__________________
Cheers.