On the Trigger tab you define Rules that link triggering gameplay tags to Consequence Events. For each rule, you can define conditions that must pass in order for the event to be selected as the best option.
Trigger tags should start with Consequence.Triggers.
It's possible to bypass the rules system and directly play a specific Consequence Event in game without using Trigger rules at all, but to take advantage of the power of Consequence, it's best to set up all dialogue to trigger via rules. That way if you want to change what trigger tag results in a specific dialogue, or what facts are required to play a dialogue, you can do that all in Consequence.
See Trigger Events in Engine for Unreal-side event triggering instructions.