Requirements

Node.js (v16)
npm
ngrok (for testing)

Create a slack app

Go to https://api.slack.com/apps?new_app=1
Click on "Create New App"
Click the "From manifest" tab
Select workspace and click "Next"
Copy the content of the file slack_app_manifest.yaml , update domain name and paste it in the "App manifest" field
Click "Create"
Click "Install to Workspace"
Click "Allow"

Update environment variables

Go to https://api.slack.com/apps
Click on the app you created
Click on "OAuth & Permissions"
Copy the "Bot User OAuth Token" and update the value of SLACK_BOT_TOKEN in the .env file
Click on "Basic Information"
Copy the "Signing Secret" and update the value of SLACK_SIGNING_SECRET in the .env file

Add app to channel

Go to channel you want to add the app to
Click on the channel name
Click on Integrations
Search for the app you created and click on it
Click on Add to channel

Install dependencies

npm install

Run application

npm run start

Update nginx configuration

Update the server_name in the file nginx.conf with your domain name
link the file nginx.conf to the sites-enabled directory
Restart nginx