Integrating slack with heroku orbs

Deployments
,
1

Hi Team,
I am deploying my node js project in Heroku using the heroku/deploy-via-git , Now I want to add slack notify functionalities after success or failed deployment. But am not able to put my head around it because am so new to Circle CI any he;p will be highly helpful. below is my confiy.yaml

orbs:
  node: circleci/node@4.1
  heroku: circleci/heroku@1.2
  slack: circleci/slack@4.1

workflows:
  sample:
    jobs:
      - node/test
      - heroku/deploy-via-git:
          requires:
            - node/test # only run deploy-via-git job if the build job has completed
          filters:
            branches:
              only: develop # Uncomment this line
          post-steps:
            - slack/notify:
                event: pass
                template: basic_success_1
            - slack/notify:
                event: fail
                template: basic_fail_1