For message formatting instructions, see this dedicated page.
1. Create app
Go to the Slack page to create apps and create a new app. Call it "PostHog" and connect it to the workspace of your choice.
Feel free to use an image from here as the app's logo.
2. Create webhook
Go to the 'Incoming Webhooks' page for your newly-created app and toggle 'Activate Incoming Webhooks' to turn it on. Then click on 'Add New Webhook to Workspace' and select the channel that the notifications will be posted to:
3. Setup webhook in PostHog
Copy the Webhook URL into the PostHog Setup page:
4. Add to action
For each action that should be posted to Slack, select "Post to webhook when this action is triggered":