Hello!
Since you did not attach your trigger file, I have made a trigger example which you can then adjust for your needs (as obviously it is not visible from your screenshot how the min_mtch variable and other variables/constants have to be initialised).
See the file attached, pay attention to the trigger called "deleting market". You need to copy that trigger and insert it into your trigger block (by pressing the "Paste Trigger" button). After you have inserted it, open its conditions and edit the first condition. You need to click on the field where the trigger name is in the condition:
Trigger {trigger name} Number of runs per selection is greater than 0
Click on that field and choose the name of your trigger that does the backing. Then save and reload the triggers.
You can first open the attached file, press the "Copy" button to copy the trigger into the clipboard, then open your original trigger file and insert the trigger from the clipboard in there.