Hi dewdle,
Dialogues are triggered through the ‘Use’ interface function in BPC_Dialogue. If you already have an interaction system, you can simply call that function from your interaction system.
If you don’t already have an interaction setup, there are 2 options provided with the Dialogue System. BPC_UseScanner is the one used in the demo, but another called BPC_MouseUseScanner could be used for your scenario instead.
Both scanners follow the same setup as the demo and tutorials, so you can check those out to see how to implement it.
Cheers!