To install the Slack integration, select Add to Slack button at the top of the Slack Integrations page:


You'll be prompted to either enter your Slack workspace URL (you must be an administrator for the workspace to install the app) or to create a new workspace:


After you enter your URL and select Continue you'll be taken to the final set-up screen that tells you how will interact with your workspace:


Once the app has been installed on Slack it will show up on the bottom left of your Slack workspace in the Apps section. The first message from the app will contain a welcome message with instructions on how to use the app and where to get help: