To set up a webhook that will be able to post feedback results directly to Slack please follow the directions in this article: How to create an outgoing webhook?. The instructions below will walk you through the steps you need to take on the Slack side to be able to receive the incoming data from Mopinion.
Instructions
These are the specific steps you need to take in Slack to set up an endpoint for the webhook
Create a Slack app
Enable Incoming Webhooks from the settings page
After the settings page refreshes, click Add New Webhook to Workspace
Pick a channel that the app will post to, then click Authorize
Use the Webhook URL to post messages to Slack
The Webhook URL you have created is the endpoint you need.
You can now specify what data must be sent, you can continue with step 4 of this article: How to create an outgoing webhook?.