Click on Slack Commands in the left side panel and then press the button labeled Create New Command
Next fill out the form with the following information and press the “Save” button:
Command: test
Request URL: [YOUR NGROK HTTPS URL]/test
Short Description: Test command
Usage Hint: [name]
We are creating a slash command called test, when initiated in Slack, this command will make a POST request to our server using the ngrok https url for our app (remember the ngrok url is unique to your server)