Although it's not complex to do it's very complex to give any sort of "follow through" instructions since there are dozens of things that can go wrong in the process.
What I can say is that:
- You don't need to re-install slick since it comes built in with the Showcase theme.
- Make sure to run slick() only after both the dom content is ready and slick has been initialized.
- Double check that you have an HTML structure that is ready to work with slick. Take a look at the documentation to double check how that would look like.