Hello!
Please see your sample triggers attached. Since you did not specify the type of bet, I'll assume it is laying, just like in the trigger example I referred to in the other forum topic.
So in the constants you can set the size of bet, the rank of the favourite to lay on and the amount of time to wait before placing a bet (in percentage of the total race duration).
To control the flow of the triggers, you can watch two trigger expressions in the View User Variables window (see the image attached). The first one is (now_time - event_off)/mf_second, the amount of time in seconds that has passed since the start of the race. The second one is raceTime, the average duration of a race with this length.
If raceTime is equal to 0, you might want to check if the race is a UK race with its length noted as "2m 3f" for example.
Make sure you've tested the triggers in Test Mode.