You have to decide whether you want to be notified by e-mail or via API webhook.
E-Mail
If you choose the email notifiaction you only have to enter your email and you will be informed whenever there is any news on one of the websites.
API Webhooks
When you choose webhook you have to define a URL, a method and a payload that will be sent whenever there are changes. You have the following variables at your fingertips: url, link, text, raw, markdown, diff, diffMrkdwn (Slack Blocks)
Slack Messages
As you can see in the example, you can also use a webhook to send you news from websites in a Slack channel: