You must first have Node.js and NPM installed.
Then you can install Bower using the command:
npm install -g bower
With these installed, you should be able to build the code with the command:
npm run build
This outputs the resulting code in dist/example.js, as well as libraries in the output directory. You should then be able to open dist/index.js in your web browser, and see the UI.
You can revert the latest "Routing and Navigation" commit, or you can go into src/Main.purs and change the main function to just call runUI on one of the components from another file. For instance, Counter.purs. Make sure to rebuild after you do this.