1. Sign in to [Slack](https://slack.com) (https://YOURSUBDOMAIN.slack.com/services)
1. Click on the Integrations menu at the top of the page.
1. Add a new Integration.
1. Pick Incoming WebHooks
1. Choose the channel name you want to send notifications to, in the Settings section
1. Add Integrations.
- Optional step; You can change bot's name and avatar by clicking "change the name of your bot", and "change the icon" after that you have to click "Save settings".
Now, Slack is ready to get external hooks. Before you leave this page don't forget to get the Token that you'll need on GitLab. You can find it by clicking Expand button, located in the "Instructions for creating Incoming WebHooks" section. It's a random alpha-numeric text 24 characters long.
*P.S. You can set "branch,pushed,Compare changes" as highlight words on your Slack profile settings, so that you can be aware of new commits when somebody pushes them.*