Setting up Slack is rather easy to do. You'll need a Slack API Token and the room you want to post the message to. Make sure to ensure that you have made the room 'private' and given your bot user access to the room
Slack has a pretty decent guide on getting a token setup here for you to follow.
Tokens were chosen for slack over webhooks, because they're more expansive. One token can post to multiple rooms with no permissions issues, so it's easier to work with these where available