How do I define my conversation topics?

Intercom uses machine learning to automatically define conversation topics for your workspace from your conversation history.

You can also manually suggest topics, and tell Intercom to exclude certain keywords, by clicking on the New topic button in the top right corner of the Conversation topics report screen.

I've started adding conversation topics, but no suggestions have been automatically generated. Why is this? There's no shortage of conversations via Intercom, and I've waited overnight since the function was enabled. Thanks.