Use firestore collections to answer questions in Vertex AI Search and Conversation

[LikeADemonicMin]

Hi! 

I'm new to GCP and actually struggling with something for days now : I want to create a chatbot that answers questions about events such as "what are the events on this week-end?", "what events are free?", "I like cinema, what can I do tomorrow?" etc. 
So, I've created a firestore collection in which I have all the informations about events like "start", "end", "price", "city", ... all I need to know! 

My problem is : I don't know how to make the link between my firestore collection and my agent in vertex AI search and conversation. For now, I've tried to export my firestore collection to bigQuery and use it as a FAQ datastore but that doesn't work. I've already read this topic : https://www.googlecloudcommunity.com/gc/AI-ML/In-vertex-AI-conversation-BigQuery-in-datastore-is-not... and maybe what I'm trying to do is not possible or I'm doing it the wrong way? 

Thanks in advance!