How do I set up a text trigger?
You may head to "Trigger" and locate "Keyword", then type your text in to the "keyword" area.
Why couldn't I save the trigger?
Please check if you have created the trigger in the "Advanced" setting previously. If so, you could not apply the "Basic" setting to your trigger because the "Advanced" setting will override the "Basic" setting.
What is payload?
Payload is usually used for button clicks by users. You can name your payload in anyway you want, you just need to note that payload name is case-sensitive and it has to match with the payload you set in the responses to trigger that particular response.