Webhooks are a way to get messages/notifications through discord, about any changes made to a board.
FIrst of all, make sure that you Trello account has been connected. In order to create a webhook, you must either have a role with the name
Trello, or have administrator privileges.
To start creating a webhook, you can use the
/webhook add command and select a board you want updates in. After you have selected a board, you can choose which webhook you want to use to send updates to or create one from scratch.
After selecting or creating a Discord webhook, you should get a confirmation message via the new webhook. After this, any new updates to your boards will be shown.
For more information, head to the Webhook Commands section where these commands are explained in greater detail.