You first need to install Haskell's Stack using their official instructions for your operating system. After that, clone the bruijn repository using

$ git clone
$ cd bruijn

Then, run bruijn using stack run. This starts bruijn's REPL. You can now play around with bruijn.

Passing normal arguments to bruijn with stack can be done with stack run -- [args]. If you enjoy it, you can install bruijn into your stack path using stack install.

Please create an issue on GitHub if you encounter any issues.