To configure webhooks, you need a webhook inbox so you are able to receive and handle incoming webhooks.
When you set up an webhook inbox, go to "Settings > Integration > Webhooks" and select all the wanted webhooks from the list. Now enter the webhook inbox URL and press the "Assign" button. On the right side you can see now all active webhooks. If you want, you can send webhooks to different URLs as well.
To check if the webhook inbox is set up correctly, you can fire a test webhook by pressing the "Test URL" button. When you want to check if all webhooks are set up correctly, you can go to "Logs > Webhooks" and filter for the wanted webhooks using status filters, event filters and date filters.