Hi
TRIGGER:
Action: back
Selections: Favourite
Conditions:
Markets name contains "Match Odds"
and selections index is less than 3
The above will back the favourite team (best odds).
Selection index 3 is "The Draw" so the trigger finds the "favourite" of the 2 teams (indexes 1 and 2).
The "overall" checkbox refers to trigger number of runs. From the manual:
Trigger Parameters
1.Number of runs
The number of times the trigger with the chosen name has been executed. If "overall" is ticked, this number is cumulative for all markets that have been refreshed since the start of the program. Otherwise this number is counted only for the current market.
When the block that the trigger belongs to is set to repeat more than once, this number is reset each time the block is repeated.