Slack Credential:

• To create a connection, navigate to the Connection section

• Click on Add Credentials
  

• A window appears. From the Application dropdown, choose Slack.
• Click on Next button

• A form will be presented for you to enter the required details.
• Enter a Secret name for your credential.
• Provide the Token

• After filling the form , click on Submit button

• The created Slack credential will appear in the list of credentials.