Create a new Discord channel on your server, for example, #ai-support.
Make sure Wallu has permission to send messages on that channel by typing !wallu there.
Open the admin panel and make sure you have at least one custom document.
See adding documents. Alternatively, you can add https://example.com to test this.
Find the channel you just created (you can use the search)
Click "override parent settings". Otherwise, the channel inherits the category's or server default settings.
Enable "Answer all messages" under "Answer messages". See the example below:
Save the changes.
You can also change the maximum length of the answers in the channels page.
Go back to Discord and try just sending a question.
If you used example.com, you can try asking can I use the domain without asking for permissions? as https://example.com has an answer to that question.
If the bot is not responding, try !wallu to debug the issue. It should always respond to !wallu if it can read and send messages on the channel and it may say why it's not responding to your questions.